In general, metal wires expand when they are heated. To test this, you heat a piece of wire and then measure how much the wire’s length changed as a result of the temperature change. In this experiment, what is the wire’s temperature?

Independent Variable

A student records the rising and setting times of the moon each day for a month.

• Controlled experiment
• Observational Study

Observational Study

Scientists at a volcano observatory continuously monitor the ground movements and volcanic gas chemistry between and during eruptions.

• Controlled experiment
• Observational study

Observational Study

A group of students sprinkle salt onto one of two burning candles and record the color of the two flames.

• Controlled experiment
• Observational study

Controlled experiment

When scientists want to determine the hardness of minerals, they use a test called the Mohs test. An experimenter trying to identify a mineral will scratch the surface with a set of tools of various hardness and then analyze the results against charts.

• Controlled experiment
• Observational study

Controlled experiment

The first evidence that light has a finite speed and does not travel from place to place instantaneously came in the 17th century from observations that Jupiter’s moons appear later when Jupiter is farther from Earth as compared to when Jupiter is closer to Earth. This phenomenon was used to show that the difference in the time of appearance of the moons is consistent with a measurable speed. What is this is an example of?

• A controlled experiment
• An observational study
• A laboratory experiment

An observational study

What is an example of a laboratory study?

• Scientists in Tokyo measure the speed of seismic waves propagating from below Arkansas through the Earth’s crust.
• Scientists notice there are fewer fish in a lake, so they measure the pH of the pond water to check for any pollutants.
• Scientists combine two organic substances in a test tube and measure the amount of product that forms.
• Scientists climb on top of a mountain to study how a rock formation originated.

Scientists combine two organic substances in a test tube and measure the amount of product that forms.

You heard somewhere that salty water boils faster than pure water. You decide to do a scientific investigation to determine whether this is true. You get three identical pots. You put 4 cups of pure water in the first pot. In the second pot, you put 4 cups of water with 2 tablespoons of salt added. In the third pot, you put 4 cups of water with 4 tablespoons of salt added. Next, you heat all three pots at the same level of heat and measure how long it takes the water in each pot to boil. What type of experiment is this?

Controlled

The time needed for the water in each pot to boil depends on several factors, such as the amount of liquid you use, the level of heat you use, and the size and composition of the pots you use. In this experiment, these are examples of variables. In this experiment, what type of variable is the salinity (concentration of salt) of the water ?

Independent

A group of scientists studies the nature of earthquakes by passing mechanical waves through various materials in a lab. Which type of model are the scientists are using?

Physical model

Which type of model is Newton’s second law of motion, which explains the relationship between force, mass, and acceleration, F=ma?

Mathematical model

Which type of model is a picture of the solar system an example of?

Conceptual model

Which type of model is a light bulb used to model the sun as a source of energy an example of?

• Mathematical model
• Conceptual model
• Physical model

Physical model

Which model could be used to illustrate rocket propulsion?

• A balloon filled with air with its stem pinched but not tied, which is then released so the balloon moves opposite the direction in which the air is ejected
• Ice crystals forming in a sealed chamber
• A scotch mint (large, round white mint candy) is dropped into a bottle of diet soda, which causes bubbles to form and an eruption to happen
• A coiled spring held by two people at opposite ends of a hallway being shaken up and down

A balloon filled with air with its stem pinched but not tied, which is then released so the balloon moves opposite the direction in which the air is ejected

A student records the amount of sugar that can be dissolved in water at four different temperatures. The amount of sugar that dissolves increases with increasing temperature. How would you describe these variables?

• Inversely proportional
• Directly proportional
• No correlation

Directly proportional

A student measures the volume of a rubber ball subjected to increasing values of uniform pressure. The volume of the ball decreases as the pressure increases. How would you describe these variables?

• Inversely proportional
• No correlation
• Directly proportional

Inversely proportional

Increasing temperature is associated with higher humidity levels in lake environments. That is, the temperature is positively correlated with humidity levels. What is the likely cause of this correlation?

• Higher temperatures cause oxygen and hydrogen to react to form water, thereby increasing humidity
• Temperature increases convert dust into water, thus increasing local humidity
• Increases in temperature cause an increase in the lake's evaporation rate

Increases in temperature cause an increase in the lake's evaporation rate

A group of students measure how much sugar they can dissolve in water at different temperatures. Their results are shown on the graph.

What is the independent variable of this graph?

• Amount of sugar dissolved
• Temperature

Temperature

Does this graph show a correlation? If so, what type of correlation?

• Yes, the amount of sugar dissolved is positively correlated with temperature.
• Yes, the amount of sugar is negatively correlated with temperature.
• No, there is no correlation.

Yes, the amount of sugar dissolved is positively correlated with temperature.

The upward trend of the data indicates a positive correlation.

A student places a pan containing 100 milliliters of water outside for 20 days. The student measures the amount of water in the pan after 5, 10, 15, and 20 days. The results are shown in the graph.

Which type of correlation does the graph show?

• Negative correlation
• Positive correlation

Negative correlation

What is the best description of the causal relationship between these variables?

• The amount of water is increasing over time due to rain.
• The passage of time makes water disappear.
• Longer periods of evaporation remove more water.

Longer periods of evaporation remove more water.

What best describes length?

• Interval between two events
• Distance between two points
• Amount of matter in an object
• The quantity that tells you how hot something is

Distance between two points

What best describes mass?

• Distance between two points
• The quantity that tells you how hot something is
• Amount of matter in an object
• Interval between two events

Amount of matter in an object

Why is it important for scientists to use the same units for measurements?

• There is only one unit of measurement that is truly scientific.
• Using the same units enables scientists to easily exchange ideas and compare the results of their measurements with their colleagues around the globe.

Using the same units enables scientists to easily exchange ideas and compare the results of their measurements with their colleagues around the globe.

What is an SI unit of length?

• Second (s)
• Kilogram (kg)
• Meter (m)

Meter (m)

What is an SI unit of mass?

• Meter (m)
• Minute (min)
• Pound (lb)
• Kilogram (kg)

Kilogram (kg)

What is an SI unit of time?

• Meter (m)
• Foot (ft)
• Kelvin (K)
• Second (s)

Second (s)

What is an SI unit of temperature?

• Second (s)
• Hour (h)
• Kelvin (K)
• Meter (m)

Kelvin (K)

Would the mass of a truck be more than, less than, or about equal to 1,000 g?

• More than
• Less than
• About equal to

• More than

Would the height of a tall building be more than, less than, or about equal to 100 cm?

• Less than
• More than
• About equal to

More than

Which symbol stands for milli-?

• n
• m
• M
• c

m

Which symbol stands for micro-?

• M
• μ
• m
• n

μ

Which symbols stand for nano-?

• m
• μ
• n
• c

n

Which symbol stands for mega-?

• k
• c
• m
• M

M

Which symbol stands for kilo-?

• m
• k
• c
• d

k

Which symbol stands for centi-?

• d
• μ
• k
• c

c

What is the approximate length of a thumb?

• 5 mm
• 5 dm
• 5 cm

5 cm

What is the approximate thickness of a piece of lead in a mechanical pencil?

• 1 cm
• 1 mm
• 10 cm

1 mm

What is the volume of a 2 L soda bottle?

• 2 mL
• 2,000 mL
• 200 mL

2,000 mL

What is a gallon of milk approximately equivalent to?

• 400 mL
• 4 L
• 4 mL

4 L

Which of the following is a derived unit?

• Inches
• Meters
• Square meters
• Moles

Square meters

Which quantity has derived units?

• Depth
• Distance
• Time
• Volume

Volume

A car is driving 60 km/hr due east. What information does this give you about the car?

• Speed
• Velocity

Velocity

A ball is initially moving down a ramp with an increasing velocity. Which term describes the ball's acceleration at that instant?

• Acceleration by speeding up
• Not accelerating
• Acceleration by changing direction
• Acceleration by slowing down

Acceleration by speeding up

What does acceleration represent a change in?

Select two answers.

• Speed
• Direction
• Distance
• Mass

• Speed
• Direction

Which of the following involves an acceleration?

Select two answers.

• An airplane slowing down as it prepares for landing
• An airplane maintaining a constant speed
• An airplane powering up the engines while at rest
• airplane banking to the east after takeoff

• An airplane slowing down as it prepares for landing
• airplane banking to the east after takeoff

Consider a block resting on a flat surface. When a force is applied to the block as shown, which arrow shows the direction of the acceleration that results?

• Left
• Down
• Right
• Up

Right

Suppose the grocery cart is at rest, and you push it to accelerate it into motion. How does the result differ if you pushed with a force of 40 N instead of 20 N for the same amount of time?

• The cart ends up moving faster compared to before.
• The cart ends up moving slower compared to before.

The cart ends up moving faster compared to before.

What is true about the net force from two equal forces in opposite directions?

• The net force is to the right.
• The net force is twice as strong.
• The net force is to the left.
• The net force is zero.

The net force is zero.

Forces acting on an object that combine to give zero net force are said to be balanced. Why would that term be appropriate?

• The forces are equal in magnitude and cause acceleration to the left.
• The forces point in opposite directions and cause acceleration to the right.
• The forces look nice and are harmonious.
• The forces cancel each other and cause zero acceleration.

The forces cancel each other and cause zero acceleration.

Let us consider the coffee mug again. The force from the hand holding it exerts a force pushing it up. Its weight exerts a force on it pulling it down. The two forces combine to produce a net force.

When the two forces are equal, what is the resulting net force?

• Upward
• Zero
• Downward

Zero

When you first exert extra force upward, what happens to the weight of the cup?

• It increases.
• It remains the same.
• It decreases.

It remains the same.

The weight of the cup, which is the force of gravity on the cup, does not change when the hand holding it exerts a stronger force upward.

The weight of the cup is less than the force from your hand. What is the net force on the cup?

• Downward
• Upward
• Zero

Upward

When two forces act in opposite directions on the same object, the net force is in the direction of the stronger force, which means the force with the greater magnitude.

How does the cup accelerate as a result?

• Downward
• Upward

Upward

The cup accelerates in the direction of the net force.

What is true of a hypothesis?

• It has been proved true.
• It remains to be tested.
• No evidence can prove it untrue.
• It seems very unlikely to be true.

It remains to be tested.

Which statement is testable?

• The moon is made entirely of cheese.
• No alien spaceships have ever landed in the United States.
• Invisible, undetectable space aliens have been visiting Earth for centuries.

The moon is made entirely of cheese.

The moon rocks collected on the Apollo space mission to the moon already show the statement to be false. So the statement is testable.

Law of conservation of matter

• Tested by experiment
• Statement about something specific observed in nature
• Intended to be universal

Tested by experiment

The law only describes amounts of matter not changing.

• Intended to be universal
• Tested by experiment
• Statement about something specific observed in nature

Statement about something specific observed in nature

The law of conservation of matter is specific because it describes only how matter fails to be created or destroyed in a chemical reaction.

The law would also apply to chemical reactions in another galaxy.

• Statement about something specific observed in nature
• Tested by experiment
• Intended to be universal

Intended to be universal

The law of conservation of matter is universal because it is a statement of what happens everywhere in the universe, not because it deals only with matter failing to be created or destroyed in a chemical reaction.

Which is a description of a scientific law?

• A statement based on many experiments that energy is never created or destroyed
• Noticing that an apple falling from a tree speeds up as it falls
• The statement "Nature hates a vacuum."
• A proposed idea to test whether cold water sinks when added to warmer water

A statement based on many experiments that energy is never created or destroyed

A law is a concise statement based on many experiments or observations.

Which definition describes a scientific theory?

• A well-tested explanation
• A law that has been tested over and over
• A guess about why and how things happen
• A tentative assumption

A well-tested explanation

A theory is a thoroughly tested explanation of a group of phenomena.

Which property must a testable statement have?

• It is capable of being shown untrue.
• correct It is untrue.
• All attempts to prove it false fail.
• It has been proved false.

It is capable of being shown untrue.

The statement does not have to be actually false, let alone proved false, to be testable. There only has to be a means to test for its possible falsehood.

A spaceship is on a robotic mission to an outer planet of our solar system.

Is it necessary for the spacecraft to continue firing its engines to keep it moving toward its destination?

• Yes. An object must continue being pushed to keep it moving.
• No. The spacecraft remains in motion when no net force is acting on it.
• Yes. Friction would bring it to a stop otherwise.
• No. The rocket engine provides a net force after being turned off.

No. The spacecraft remains in motion when no net force is acting on it.

According to Newton’s first law, it will remain in motion at constant velocity.

Two people are both pushing on a ball with equal force in opposite directions. On person suddenly stops pushing. What will happen to the ball?

• It will begin accelerating.
• It will immediately fall due to gravity.
• It will begin moving with constant speed.
• It will begin to reach terminal velocity.

It will begin accelerating.

If the net force on an object increases, what happens to its acceleration?

• It increases.
• It remains the same.
• It decreases.

It increases.

If the mass of the object is greater, what happens to the acceleration from the same force?

• It is smaller.
• It is greater.
• It is the same.

It is smaller

How is the net force applied to an object and the acceleration it produces related?

• Directly
• Inversely

Directly

How is the mass of an object and the object’s acceleration related?

• Directly
• Inversely

Inversely

To produce the same acceleration with larger mass, what change would need to be made to the net force?

• It would need to be larger.
• It would need to be smaller.
• It would need to be the same.

It would need to be larger.

If the force acting on the box increases, what will happen to the box's acceleration?

• It will increase.
• It will decrease.

It will increase.

If the mass of the box increases, but the force remains the same, what will happen to the box's acceleration?

• It will increase.
• It will decrease.

It will decrease.

When the diver is moving downward and is bending the board downward, what is the force of the diver on the board compared to the force of the board on the diver?

• It is equal.
• It is smaller.
• It is greater.

It is equal.

When the diver has bent the board downward as far it bends, what is the force of the diver on the board compared to the force of the board on the diver?

• It is equal.
• It is smaller.
• It is greater.

it is equal.

When the diver is moving upward because of the force from the board, what is the force of the diver on the board compared to the force of the board on the diver?

• It is smaller.
• It is equal.
• It is greater.

It is equal.

When the diver is being accelerated upward by the board unbending, what is the force of the diver on the board compared to the force of the board on the diver?

• It is equal.
• It is greater.
• It is smaller.

It is equal.

When the diver is no longer in contact with the board, what is the force of the diver on the board compared to the force of the board on the diver?

• It is smaller.
• It is greater.
• It is equal

It is equal

Which force shown in the diagram needs to be included when determining the net force on the cart?

The forces are shown with arrows in the diagram.

• F _floor
• F _foot
• F _person
• F _cart

F _person

A basketball player makes a jump shot. What directly exerted an external force on the player to accelerate him upward into the air?

• The floor
• The basket
• His knees
• His feet

The floor

A bumper car at an amusement park bumps into the back of another. The car in front moves faster as a result of the collision, and the car behind it is slowed by the collision. The cars have unequal mass. Which car experiences the greater force during the collision?

• The more massive car experiences the stronger force.
• The car in front experiences the stronger force.
• The less massive car experiences the stronger force.
• Each car experiences a force of the same magnitude.

Each car experiences a force of the same magnitude.

When a soccer ball falls, it is accelerated toward Earth while Earth does not move noticeably in response. What is the likely explanation?

• Both previous statements are true.
• Gravity causes planets to attract objects, not the reverse.
• Earth pulls more strongly on the soccer ball than the soccer ball pulls on Earth.
• The soccer ball accelerates more because its mass is small compared to Earth’s mass.

The soccer ball accelerates more because its mass is small compared to Earth’s mass.

One of the members of a river research team measures how far a floating object has traveled at 5.0 second intervals. The intent is to calculate the speed of the water at the center of the river and collect similar data for other rivers.

In measuring the distance at each time, what is the independent variable?

• Speed
• Time
• Distance

Time

Distance is the measured quantity that seems to respond to the other variable—the other variable is the independent variable.

One of the members of a river research team measures how far a floating object has traveled at 5.0 second intervals. The intent is to calculate the speed of the water at the center of the river and collect similar data for other rivers.

What is the dependent variable?

• Distance
• Time
• Speed

Distance

The speed is merely calculated from the other two variables.

A scientist is studying the speed of water flow in rivers by this method. Which type of study would this be classified as?

• A field study
• A laboratory study

A field study

A field study would describe going to the actual river to do the investigation.

A scientist is studying the speed of water flow in rivers by this method. Which type of experiment is this an example of?

• An uncontrolled experiment
• A controlled experiment

An uncontrolled experiment

A field study almost always has hidden variables that the researcher collecting the data cannot hold constant.

What is an experiment in which you deliberately change only one variable and observe how a second variable changes as a result while you hold all other variables that you control constant?

• An observational study
• A field study
• An uncontrolled experiment
• A controlled experiment

A controlled experiment

A controlled experiment is one in which you keep all other variables other than dependent and independent variables constant.

What is a model in science?

• A simpler system that is analogous to the real system
• A law that has not yet been adequately tested
• An exact replica of the real system of interest
• A theory that explains the real system but has not been fully tested yet

A simpler system that is analogous to the real system

If it were an exact replica, it would not be simpler and easier to examine than the real system.

Which quality identifies a scientific statement as testable?

• It cannot be proved true.
• It is untrue.
• There is a way to test it for falseness.

There is a way to test it for falseness.

Many statements cannot be fully proved true because there is no way to test every single instance of the situation.

Which term describes something that tentatively assumes what happens or how it happens in order to test what it assumes?

• Theory
• Model
• Hypothesis
• Law

Hypothesis

A hypothesis is a tentative statement intended to be tested.

The water flowing in a river comes from rain and snow that collected and eventually ran into rivers. As the river flows to the sea, water evaporates from it, and from all over Earth’s surface, back into the atmosphere, where the water can fall as rain and snow again. A team carries out an investigation, and it proposes that maybe the moist air is being cooled when the wind from west to east forces the air upward, based on knowledge that temperatures tend to decrease with increasing height. Which term describes this step?

• Constructing a scientific explanation
• Formulating a hypothesis
• Using a model
• Conducting an observation

Formulating a hypothesis

Proposing, or even just thinking of, an idea to then test is formulating a hypothesis.

The graph shows the volume of a copper cube as a function of temperature. What is the relationship between volume and temperature in this plot?

• They are not correlated.
• They are inversely proportional.
• They are directly proportional.

They are directly proportional.

When data points form a line with a positive slope this indicates that the variables are directly proportional.

The plot shows the volume of a gas measured at different pressures. What does this data tell you about the relationship between these variables?

• They are directly proportional.
• They are inversely proportional.
• They are not correlated.

They are not correlated.

The negative downward slope of the data trend indicates an inversely proportional relationship.

The following table shows elevation of a weather balloon measured as a function of time after its launch. What do the data indicate about the relationship between these variables?

Time (hours) Elevation (meters)

5 1017

10 1019

15 1007

20 1008

25 1018

30 1013

35 1020

40 1007

45 1003

50 1020

• They are not correlated.
• They are directly proportional.
• They are inversely proportional.

They are not correlated.

The lack of any positive or negative slope to the data points indicates that they are not correlated.

What is the zero point of an x-y scatterplot called?

• Origin
• Slope
• Y-intercept

Origin

The point where both the x and y variables are zero is, by definition, the graph’s origin.

A graph shows a positive correlation between temperature on the x-axis and total rainfall amounts on the y-axis. Does this indicate that higher temperatures directly cause the higher rainfall amounts?

• The correlation does not necessarily mean that there is a causal relationship.
• Indeterminate, there is no way to know one variable has a causal relationship with another variable.
• The positive correlation between variables always means that there is a causal relationship.

The correlation does not necessarily mean that there is a causal relationship.

By using science methods and critical thought the causal relationships between variables can be established.

Which tool would be used to calculate the amount of space taken up by 10 irregularly shaped ice cubes?

• Graduated beaker
• Ruler
• Thermometer
• Digital scale

Graduated beaker

A graduated beaker can be used to determine the volume of the cubes.

A recipe calls for 300 g of whole-wheat flour. What tool would be used to measure the flour?

• Meter stick
• Beaker
• Balance

Balance

A balance is used to measure mass.

Which cooking measurement is categorized as a derived unit?

• The time needed to cook a steak
• The length of a cake pan
• The temperature of an oven
• The volume of cream used in a dessert

The volume of cream used in a dessert

Volume is a derived quantity, not a base quantity.

Which statement is correct?

• Density is a base unit.
• Area is a base unit.
• Length is a derived unit.
• Speed is a derived unit.

Speed is a derived unit.

Speed is derived from the base units of length and time.

. Why is it important to have standard measures for physical quantities?

• To allow scientists from other countries to use standard measures and not make up their own units
• To allow for the comparison of measurements with anyone familiar with the measurement system
• To make measurements, such as length, easier to perform
• To make it more difficult for scientists to exchange and compare results of their measurements

To make it more difficult for scientists to exchange and compare results of their measurements

Measurements are only useful if their values are meaningful to others.

Which unit is categorized as a base unit?

• g/cm³
• km/hr
• m/s
• meter

meter

Only the length unit is involved, which is independent of the other derived units listed.

What is the official SI base unit for mass?

• Meter
• Second
• Gram
• Kilogram

Kilogram

Although a gram measure mass, it is not the official SI base unit for mass.

What is the official SI base unit for length?

• Kelvin
• Meter
• Kilometer
• Gram

Meter

The meter measures length.

What is the official SI base unit for time?

• Hour
• Kilograms
• Second
• Meters/second

Second

Seconds measure time.

Which of these has values that are expressed in terms of a derived unit in the SI system?

• Length
• Time
• Area
• Mass

Area

Area is equal to the length times the width of an object.

Which unit is categorized as a derived unit?

• Kilogram
• Kilometer/second
• Second
• Meter

Kilometer/second

Kilometers per second combines two base units to make a derived unit.

Which characteristic of a sample of liquid does a graduated cylinder measure?

• Weight
• Mass
• Volume
• Density

Volume

Volume is the amount of space an object takes up, often measured by the water displacement test.

A cargo spacecraft that brings supplies to the International Space Station (ISS) is launched using rocket propulsion. The spacecraft’s rockets fire hot gases backward. Which statement is true about this situation according to Newton’s third law?

• The force that the rocket exerts on the hot gases is equal and opposite to the force the hot gases exert on the rocket.
• Therefore, the two forces cancel, and the rocket does not accelerate. The rocket will accelerate forward because the gases push it off the ground.
• When the rockets fire hot gases backward, this creates huge forces in the opposite direction, exerted on the spacecraft by the hot gases.

When the rockets fire hot gases backward, this creates huge forces in the opposite direction, exerted on the spacecraft by the hot gases.

The hot gases create a reaction force on the spacecraft in the opposite direction.

A parachute is deployed to slow down a skydiver while descending toward the ground. What happens while the skydiver is descending?

• Their velocity points downward, and their acceleration points upward.
• Their velocity points upward, and their acceleration points downward.
• Their velocity points downward, and their acceleration points downward.
• Their velocity points upward, and their acceleration points upward.

Their velocity points downward, and their acceleration points upward.

Velocity always points in the direction of motion and acceleration in the direction of the changing velocity, which in this case means upward.

As a cargo spacecraft lifts off, its booster rockets are employed to accelerate it. Assume that the booster rockets apply a constant force on the spacecraft. The higher the spacecraft ascends, the less mass it has because some of its fuel is burned. What is happening as the spacecraft is ascending?

• Its speed decreases, and its acceleration increases.
• Both its speed and acceleration decrease.
• Its speed increases, and its acceleration decreases.
• Both its speed and acceleration increase.

Both its speed and acceleration increase.

Since the mass of the spacecraft is decreasing, the acceleration provided by its booster rockets is increasing, which causes the speed to increase accordingly.

An astronaut on board the International Space Station (ISS) gently lifts their feet off the floor of the cabin so that they are not touching any object. At that moment, the ISS rockets start to reboost and accelerate the ISS forward. What will happen to the astronaut initially?

• The astronaut will immediately accelerate with the ISS.
• To an observer accelerating with the ISS, the astronaut will appear to be accelerating backward.
• The astronaut will first be jerked backward and then pulled forward with the ISS, just like when you start driving your car at a traffic light.

To an observer accelerating with the ISS, the astronaut will appear to be accelerating backward.

They will appear to be accelerating backward because the ISS will be accelerating forward. They will not move with the ISS due to their inertia since the rest of the ISS is not exerting any force on them.

If two boxes with masses of 5 kg and 20 kg are pushed with the same force, which one will accelerate more?

• The 20 kg box
• The 5 kg box
• They will accelerate the same.

• The 5 kg box

The less massive box will accelerate more when the same force is applied.

If the net force is zero on a motorcycle traveling at 20 m/s, which statement is true concerning the motion of the motorcycle?

• The motorcycle will continue traveling at 20 m/s.
• The motorcycle’s motion will change.
• The motorcycle will come to a stop.
• The motorcycle will accelerate at a rate of 20 m/s².

• The motorcycle will continue traveling at 20 m/s.

An object will keep its same motion unless some non-zero force acts on it.

For which case is there a net force acting on the object?

• A 300 lb weight being held motionless over the head of a weight lifter
• A rocket accelerating upward at a rate of 5 m/s²
• An apple that has fallen to the ground
• A hockey puck sliding across ice at a constant speed in a straight line

• A rocket accelerating upward at a rate of 5 m/s²

Once on the ground, the apple is stationary, so it must have no net force acting on it.

A car’s engine provides a force of 200 N forward while a force of 150 N from air resistance acts to oppose the car’s motion. What is the net force and its direction on the car?

• 350 N forward
• 50 N backward
• 350 N backward
• 50 N forward

• 50 N forward

The net force is 200 N – 150 N. This gives a positive force, indicating the forward direction.

If the net force acting on an object is halved, how will the acceleration change?

• The acceleration will change in an unpredictable way.
• The acceleration will remain the same.
• The acceleration will double.
• The acceleration will be half as much.

• The acceleration will be half as much.

Force and acceleration have a direct relationship.

Two tugboats attach their lines to separate barges with the same masses in a shipping channel. If one tugboat pulls Barge A toward the west while the other tugboat pulls Barge B in the same direction, applying twice as much force, which barge will accelerate more?

• Barge A Neither, they will accelerate at the same rate.
• Neither will accelerate.
• Barge B

• Barge B

Barge B will accelerate twice as fast because acceleration is directly proportional to the applied force.

Which statement regarding inertia is correct?

• Objects with more inertia are easier to accelerate.
• Inertia is the tendency of an object to keep its same motion.
• Objects with less mass have more inertia.
• It is easier to cause objects with more inertia to change velocity.

• Inertia is the tendency of an object to keep its same motion.

The exact opposite is true. Objects with more inertia are more difficult to accelerate.

A moving van worker is trying to move a couch. Due to inertia, what does the amount of force that needs to be applied to get the couch to start moving across the room depend on?

• The size of the couch
• The distance across the the room
• The mass of the couch

• The mass of the couch

The amount of the force required depends on the mass of the object that the force is applied to.

If you press your hand downward on a book lying on a table, what is the reaction force to your hand?

• Your hand pushing the book down against the table
• Gravity pulling your hand downward
• The book pushing up against your hand
• The table pushing up against your hand

• The book pushing up against your hand

The reaction force acts backward on the object causing the action, which in this case is your hand.

Which scenario involves an action-reaction force pair?

• Two ice skaters (John and Elisa) push off from each other. As John pushes Elisa forward, his muscles push him backward, causing him to slide across the ice.
• A kangaroo pushes off the ground, and the ground pushes the kangaroo forward. correct
• A person pushes down on a chair, and the chair pushes down on the ground.
• A ball is hit by a bat, and the force of gravity pulls the ball downward.

• A kangaroo pushes off the ground, and the ground pushes the kangaroo forward. correct

The reaction force of Elisa pushing back on John is what causes him to slide backward.

Which is true regarding action-reaction forces?

• For every action, there is not an equal and opposite reaction.
• Both action and reaction forces are not real forces.
• Action and reaction forces are not always equal and opposite.
• Objects that are interacting do not have to be moving for Newton’s third law to apply to them.

• Objects that are interacting do not have to be moving for Newton’s third law to apply to them.

This is a false statement and contradicts Newton’s third law.

If the acceleration of an empty truck is 1.5 m/s², what will happen to its acceleration if it is fully loaded and its total mass doubles?

• The acceleration will be half as much.
• The acceleration will double.
• The acceleration will not change.
• The acceleration will be zero.

• The acceleration will be half as much.

The force is the same, and the acceleration is inversely proportional to the mass, so the acceleration will decrease by one-half.

A driver uses a forklift to push a full cart of bricks halfway down an aisle with a force of 20 N. If the driver pushes an empty cart the rest of the way down the aisle using the same 20 N of force, how does the acceleration of the empty cart compare with that of the full cart of bricks?

• The acceleration will be the same.
• The acceleration will be zero.
• The acceleration of the empty cart will be less than that of the full cart because it has less mass.
• The acceleration of the empty cart will be more than that of the full cart because it has less mass.

• The acceleration of the empty cart will be more than that of the full cart because it has less mass.

The acceleration is inversely proportional to mass, so the empty cart with less mass will have a greater acceleration than the full cart.

What best describes the net force acting on an object moving in a straight line at a constant speed?

• The net force is zero.
• The net force is opposite the object's direction of motion.
• The net force depends on the mass of the object.

• The net force is zero.

The net force is zero because the object does not change its motion.

What is the name of the force that always opposes the motion of an object?

• Friction
• Acceleration
• Inertia

• Friction

Friction is the force that opposes the motion of an object.

Why is a car more likely to slide if it tries to stop on an icy road than on pavement?

• Because ice has less friction than pavement does
• Because pavement has less friction than ice does
• Because ice has less inertia than pavement

• Because ice has less friction than pavement does

A car is more likely to slide if it tries to stop on an icy road because ice has less friction

When the applied force reaches about 100 N, why is the crate not moving?

• The applied force is the same as the friction force.
• The applied force is greater than the friction force.
• The applied force is less than the friction force.

• The applied force is the same as the friction force.

The applied force is equal to the friction force.

What is the crate experiencing?

• Kinetic friction
• No force
• Static friction

• Static friction

The force of static friction acts on the crate because the crate is not moving, but it is experiencing friction.

When the force on the crate is 150 N or more, why does the speed of the crate increase?

• Because both the kinetic and static frictions act in the opposite direction
• Because the static friction acts in the opposite direction
• Because there is a net force on the crate

• Because there is a net force on the crate

There is a non-zero net force acting on the crate.

After the force is removed, what does the crate do?

• It abruptly stops when you let go of the slider.
• It continues to move with constant speed.
• It gradually slows down until it stops.

• It gradually slows down until it stops.

The crate gradually slows down until it stops, because the force of kinetic friction is acting to slow it down.

. When is a force of friction not likely to exist between two objects?

• If they are sliding across each other
• If they are leaning against each other
• If one is standing on top of the other
• If they are not touching

• If they are not touching

A force of friction does not exist if two objects are not touching.

Why do you need to give a filing cabinet a stronger push to get it to start moving along the floor than to keep it moving?

• To overcome the force of static friction
• To overcome its mass
• To overcome the force of kinetic friction

• To overcome the force of static friction

The force of static friction acts to prevent the filing cabinet from starting to move.

You can start a fire by rubbing a flint rock with high-carbon steel. What is the force that lets you do this?

• Force of kinetic friction
• Force of static friction
• Gravitational force

• Force of kinetic friction

This is the force of kinetic friction because the rock and steel are moving with respect to each other.

Which factors affect the force of friction between two solid objects?

Select 2 answers.

• The types of surfaces involved
• The speed of the objects
• The surface areas of the objects
• How hard the surfaces press on each other

• The types of surfaces involved
• How hard the surfaces press on each other

Both the types of surfaces involved and how hard they press on each other affect the force of friction between two solid objects.Both the types of surfaces involved and how hard they press on each other affect the force of friction between two solid objects.

Marie pushes a box across the floor. What causes the box to move?

• The force of friction
• Marie’s force
• Mass

• Marie’s force

Marie’s force causes the box to move. Without her applied force, the object would not move.

What is the attractive force that exists between any two objects known as?

• Centripetal force
• Gravitational force
• Frictional force

• Gravitational force

Gravitational force is the attractive force that exists between any two objects.

What is the force that keeps a planet in orbit around the sun?

• Friction
• Gravity
• Solar force

• Gravity

The force of gravity keeps a planet in orbit around the sun.

Earth's mass is much greater than that of the moon. If you were to stand on the surface of the moon, what would the gravitational force you would experience from the moon be?

• Weaker than the gravitational force you feel when you stand on Earth
• Stronger than the gravitational force you feel when you stand on Earth
• Equal to the gravitational force you feel when you stand on Earth

• Weaker than the gravitational force you feel when you stand on Earth

The moon's mass is smaller than Earth's, so its gravitational pull is weaker than Earth's.

Which phenomenon is an example of gravity?

• The moon orbiting the earth
• A car accelerating across a horizontal surface
• Lightning in a dark sky
• Wind moving through canyon channels

• The moon orbiting the earth

The moon orbits the earth because of gravitational attraction.

Which phenomenon is an example of friction?

• A person jogging on a sidewalk
• A piece of wood floating in a pond
• An apple falling from a tree
• An arrow hitting a target

• A person jogging on a sidewalk

Jogging is not possible without friction between your shoes and the sidewalk or track.

What is the measure of the amount of gravity acting on an object?

• Volume
• Velocity
• Acceleration
• Weight

• Weight

Weight is the measure of the force of gravity on an object.

What affects the gravitational force between two objects?

• Only the masses of the objects
• Both the objects’ masses and the distance between them
• Both the weight of the objects and the distance between them
• Only the distance between the objects

• Both the objects’ masses and the distance between them

The gravitational force between two objects is affected by both the objects’ masses and the distance between them.

With what force of gravity does Earth pull a bike compared to a truck?

• The same force
• A greater force
• A smaller force

• A smaller force

Earth pulls a bike with a smaller force of gravity because the mass of the bike is smaller.

If the distance between two objects is doubled, what happens to the force of gravity between them?

• It stays the same.
• It is decreased.
• It is increased.

• It is decreased.

If the distance is doubled, the force of gravity decreases.

What is the force of gravity exerted by the Earth on you compared to the force of gravity exerted by you on the Earth?

• It is greater.
• It is smaller.
• It is the same.

• It is the same.

The two forces are equal because of Newton’s third law.

A bicycle and a train are moving at exactly the same velocity. Which has more momentum, the bicycle or the train?

• Both have the same momentum.
• The bicycle has more momentum.
• The train has more momentum.

• The train has more momentum.

If two objects are moving at the same velocity, the more massive object has more momentum.

Now, imagine two identical trains are traveling on parallel tracks. One is moving at 10 km/hr, and the other is moving at 100 km/hr. Which train has more momentum?

• The train moving at 10 km/hr has more momentum.
• The train moving at 100 km/hr has more momentum.
• Both trains have the same momentum.

• The train moving at 100 km/hr has more momentum.

If two objects have the same mass, the faster moving object has more momentum.

One pool ball collides with another, and the balls move away from one another. Which statement is true if there are no losses to heat or friction?

• The velocity of each ball must be the same before and after the collision.
• Each ball must have the same momentum before and after the collision.
• The total momentum of both balls must be the same before and after the collision.

• The total momentum of both balls must be the same before and after the collision.

A ball rolling across a smooth floor gradually slows to a stop. Why does this occur?

• The ball disobeys the law of conservation of momentum.
• Due to friction, the ball gradually loses kinetic energy.
• The law of conservation of momentum does not apply in this situation.

• Due to friction, the ball gradually loses kinetic energy.

Which effect does static friction have on the car?

• It slows the car down once the tires lock and begin to slide.
• It tends to slow the vehicle down and is affected by the car's shape and size.
• It keeps the race car from rolling while it is parked.

• It keeps the race car from rolling while it is parked.

Which effect will kinetic friction have on the car?

• Slows the car down once the tires lock and begin to slide
• Tends to slow the vehicle down and is affected by the car's shape and size
• Keeps the race car from rolling while it is parked

• Slows the car down once the tires lock and begin to slide

Although based on popular American-made cars, NASCAR vehicles have many features that are different from ordinary cars. One example is the tires: NASCAR tires are wider and smoother with no tread. Based on your understanding from this module of the factors that affect the force of friction, what is the most likely reason for the unique design of racing tires?

• The wider, smoother tires better dissipate the heat generated during the race, leading to longer wear time and better performance.
• Wider tires with no tread have more contact area with the track, thus generating more traction.
• The tires are smooth and wide to look cool, thus attracting more fans

• The wider, smoother tires better dissipate the heat generated during the race, leading to longer wear time and better performance.

To ensure fair competition, rules are in place that govern every aspect of a NASCAR race car, including its weight. A NASCAR race car must weigh a minimum of 3,400 pounds when all required liquids and equipment are on board. Additionally, NASCAR race cars must also weigh at least 1,625 pounds on the front-right and right-rear sides of the car. This rule prevents cars from having too much weight on the left side of the car. Because NASCAR races are around tracks with left-hand turns, drivers would want to have more weight on the left side of the car to aid in turning. The right-side rule limits this advantage. Why is the force of gravity advantageous in this case?

• Because it increases the speed of the race car when going downhill
• Because it increases the mass of the car, thus increasing traction
• Because it increases the contact force with the track, thus creating more traction

• Because it increases the contact force with the track, thus creating more traction

Which scenario is a completely inelastic collision?

• A child runs into another child, and the second child falls on the ground.
• A hockey player uses their stick to strike a hockey puck and send it toward a goal.
• A basketball hits the rim of a hoop and goes in.
• Two rams start to fight by running toward each other and colliding with their heads. As a result, their horns get locked as they continue to fight.

• Two rams start to fight by running toward each other and colliding with their heads. As a result, their horns get locked as they continue to fight.

If the mass of an object is halved and its speed doubled, what will happen to its momentum?

• It will halve.
• It will increase by a factor of four.
• It will not change.
• It will double.

It will not change.

What does the law of conservation of total linear momentum state?

• That any momentum lost by one object in a collision will be gained by the other
• That the total momentum in a system is different before and after a collision
• That the momentum of any object involved in a collision does not change
• That the type of collision determines whether or not the total momentum is conserved

• That any momentum lost by one object in a collision will be gained by the other

Friction usually acts to oppose, or slow down, the velocity of objects. Which situation is an example of friction causing an increase in velocity?

• Air flow over an airplane wing
• A golf ball rolling downhill on a putting green
• The fan on an airboat
• A box sitting on a flatbed truck as the truck accelerates forward

• A box sitting on a flatbed truck as the truck accelerates forward

What is a disadvantage of friction?

• Air resistance of a parachute slows down the descent of a skydiver.
• Friction makes it possible for you to grasp items with your hand.
• Friction enables you to walk.
• Friction reduces the efficiency of engines and other machines by converting parts of their kinetic energy into heat.

• Friction reduces the efficiency of engines and other machines by converting parts of their kinetic energy into heat.

Friction is a force that usually slows down or prevents motion. However, friction can sometimes cause an object to speed up, such as when you walk forward. The frictional force between the ground and your foot is what actually pushes you forward (as your foot pushes backward on the ground). Which instance describes a scenario in which the frictional force causes the object it acts upon to speed up rather than slow down?

• A sled on snow
• Sliding a book across your desk
• A package on a moving conveyer belt
• Air resistance on a moving car

• A package on a moving conveyer belt

Which factor has no effect on the force of friction between two solid objects?

• The contact force between the objects
• The smoothness of the surfaces between the objects
• The relative speed of the objects to each other
• The type of materials the objects are made of

• The relative speed of the objects to each other

A brick is dragged across a concrete floor. Which type of friction acts between the brick and the floor?

• Rolling friction
• Kinetic friction
• Fluid friction
• Static friction

• Kinetic friction

Why is an applied force necessary to keep most objects in the world moving at a constant velocity?

• Because the natural tendency of any object is to come to rest
• Because a force is needed to accelerate an object
• Because the object’s weight acts to slow it down
• Because a frictional force opposing motion acts on most objects

• Because a frictional force opposing motion acts on most objects

Which statement is inaccurate about gravity?

• The force of gravity is what holds you to Earth’s surface.
• Only very large objects exert a gravitational force.
• It would be impossible to walk without gravity.
• Gravity is an attractive force.

• Only very large objects exert a gravitational force.

If you could stop a planet for just an instant and then let it go, what would happen to it?

• It would fall into the sun.
• It would continue orbiting the sun.
• It would spiral away from the sun into space.
• It would remain motionless.

It would fall into the sun.

Consider a box lying on a table. If another box is stacked on top of it, how will the gravitational force (weight) of the top box affect the frictional force between the bottom box and the table if someone pushes slowly on the lower box?

• The frictional force will decrease.
• It is impossible to determine how the frictional force will change.
• The frictional force will remain the same.
• The frictional force will increase.

• The frictional force will increase.

If the distance between Earth and the sun were decreased, how would the gravitational force between them change?

• The gravitational force would increase.
• The gravitational force would decrease.
• The gravitational force would remain the same.

• The gravitational force would increase

If the mass of Earth were doubled (while keeping its size the same), how much more would you weigh at the surface?

• You would weigh half as much.
• You would weigh the same.
• You would weigh twice as much.
• You would weigh four times as much.

• You would weigh twice as much.

A chemical reaction in a battery powers a flashlight.

• Potential energy
• Work

• Work

Water is stored behind a dam.

• Work
• Potential energy

• Potential energy

A door is propped open so that a spring remains stretched.

• Potential energy
• Work

Potential energy

Water flowing over a dam generates electricity.

• Work
• Potential energy

• Work

A spring pulls a door shut.

• Work
• Potential energy

• Work

Which statement describes the relationship between work and energy?

• All types of energy can be considered work.
• Work can take the form of stored potential energy.
• Work is energy that is being used or converted.
• Energy is work that is being used.

• Work is energy that is being used or converted.

A person pushes against a wall when they stretch. The wall does not move. Is work done on the wall?

• No, work is not done.
• Yes, work is done.

• No, work is not done.

A driver applies the brakes to a moving car, and the car stops. Is work done on the car?

• No, work is not done.
• Yes, work is done.

• Yes, work is done.

A person lifts a barbell off the ground. Is work done on the barbell?

• Yes, work is done.
• No, work is not done.

• Yes, work is done.

A person holds a barbell above their head. Is work done on the barbell?

• Yes, work is done.
• No, work is not done.

• No, work is not done.

A small boy cannot lift a heavy bucket off the ground, but his father can. Why?

• The man’s arms are a greater distance from the ground.
• The man can apply a larger force to the bucket.
• The man can apply more work to the bucket.
• Boys play; they do not work.

• The man can apply a larger force to the bucket.

One side of a mountain has a short, steep slope, and the other side has a long, gentle slope. Which statement is true?

• No work is done when climbing a mountain.
• More work is done climbing the gentle slope.
• More work is done climbing the steep slope.
• The same amount of work is done climbing the steep slope and the gentle slope.

• The same amount of work is done climbing the steep slope and the gentle slope.

When a flashlight uses a battery to emit visible light, what happens to the potential energy?

• It increases.
• It decreases.

• It decreases.

When a car uses gasoline, what happens to the potential energy?

• It decreases.
• It increases.

• It decreases.

When a leaf stores the energy in sunlight as sugar, what happens to the potential energy?

• It decreases.
• It increases.

• It increases.

Which is an example of potential energy?

• A stretched rubber band
• A planet orbiting a star
• A jogger on the track
• A river

• A stretched rubber band

Which is an example of gravitational potential energy?

• A car resting on a mechanic’s lift
• A kayaker paddling down the stream
• A basketball falling from the rim
• A ball rolling down a ramp

• A car resting on a mechanic’s lift

What is chemical potential energy?

• Energy stored in an electrical circuit
• Energy stored in a rubber belt stretched between two posts
• Energy associated with the motion of a baseball bat
• Energy stored in the bonds of a molecule

• Energy stored in the bonds of a molecule

Which scenario is an example of kinetic energy?

• An energy drink
• An unpicked apple on a tree
• A ball rolling down hill
• A stack of plates balanced on a table

• A ball rolling down hill

If you throw a ball made of rubber and a ball made of steel at a wall with the same force, which will have more kinetic energy and why?

• The metal ball because it has more mass
• The rubber ball because it stores more elastic energy
• The metal ball because it has a harder surface

• The metal ball because it has more mass

A person puts a pot of water on the stove and turns on the burner. The temperature of the water increases from 20°C to 80°C. Which statement about the motion of particles and thermal energy in the water is true?

• The particle motion and thermal energy increase as the temperature increases.
• The particle motion increases as the temperature increases, but the thermal energy stays the same.
• The particle motion and thermal energy both remain the same as the temperature increases.
• The thermal energy increases as the temperature increases, but the particle motion stays the same.

• The particle motion and thermal energy increase as the temperature increases.

Particle motion and thermal energy increase with temperature.

A battery stores chemical energy. When the battery is hooked up to a circuit, what is converted to electrical energy?

• Potential energy
• Thermal energy
• Electromagnetic energy

• Potential energy

When the battery is hooked up to a circuit, chemical potential energy is converted to electrical energy.

The electrical energy, in turn, can be used to produce another type of energy. For example, in a flashlight, what is the electrical energy used to produce?

• Electromagnetic energy
• Thermal energy
• Potential energy

• Electromagnetic energy

In a flashlight, the electrical energy is converted into light energy, which is called electromagnetic energy.

The flashlight might feel warm because some energy is lost as heat. What has been transferred?

• Electromagnetic energy
• Thermal energy
• Potential energy

• Thermal energy

Heat is thermal energy that has been transferred.

A battery contains chemical potential energy. When a battery is used to run a fan, what happens to the chemical potential energy?

• It is stored.
• It is used.

• It is used.

When a battery is used to run a fan, chemical potential energy is being used.

An object has gravitational potential energy due to its height above Earth’s surface. When a man carries a brick up a staircase, what happens to the gravitational potential energy?

• It is used.
• It is stored.

• It is stored.

An object has gravitational potential energy due to its height above Earth’s surface. When a man carries a brick up a staircase, gravitational potential energy is being stored.

A spring that is squeezed or stretched contains elastic potential energy. When a spring pulls a door shut, what happens to the elastic potential energy?

• It is used.
• It is stored.

• It is used.

A spring that is squeezed or stretched contains elastic potential energy. When a spring pulls a door shut, elastic potential energy is being used.

How is energy converted when a lamp is turned on?

• Electric energy is converted to light energy.
• Light energy is converted to chemical energy.
• Elastic potential energy is converted to kinetic energy.

• Electric energy is converted to light energy.

How is energy converted when a stretched rubber band launches a wad of paper?

• Electrical energy is converted to light energy.
• Light energy is converted to chemical energy.
• Elastic potential energy is converted to kinetic energy.

• Elastic potential energy is converted to kinetic energy.

How is energy converted when a plant uses energy from the sun to produce sugar?

• Electrical energy is converted to light energy.
• Light energy is converted to chemical energy.
• Elastic potential energy is converted to kinetic energy.

• Light energy is converted to chemical energy.

Which type of energy is involved with an automobile's rotating wheel?

• Thermal
• Chemical potential
• Kinetic
• Elastic potential

• Kinetic

A rotating wheel is moving and thus has energy of motion.

As an engine is lowered into a car, what happens to its potential energy?

• It decreases.
• It remains the same.
• It increases.

• It decreases.

Potential energy depends on an object’s mass and height.

What happens to kinetic energy if speed increases?

• There is no change.
• Kinetic energy increases.
• Kinetic energy decreases.

• Kinetic energy increases.

Kinetic energy increases when velocity increases.

After an engine is mounted in an automobile, a radiator is added. The purpose of the radiator is to cool the engine. To do that, which type of energy does the radiator remove from the water that circulates through the hot engine block?

• Thermal energy
• Chemical energy
• Gravitational potential energy

• Thermal energy

Thermal energy, or heat, is being transferred.

When energy is converted from one form to another, what happens to the total amount of energy?

• It decreases.
• It will change depending on the circumstances.
• It increases.
• It remains the same.

• It remains the same.

Energy cannot be created or destroyed; the total must remain constant in any process.

Many types of energy conversions occur in the assembly and operation of an automobile. Which type of energy conversion is present in the change of chemical potential energy to thermal energy?

• Lowering a vehicle on its spring suspension
• Combustion of fuel
• Turning on headlights
• Dropping a wrench

• Combustion of fuel

At the end of the assembly process, an automobile rolls off the production line, and a worker applies the brakes. Which statement describes what happens to the vehicle’s kinetic energy?

• The kinetic energy is transformed into gravitational potential energy.
• The kinetic energy is transformed into light energy.
• The kinetic energy is transformed into chemical potential energy.
• The kinetic energy is transformed into thermal energy in the brake materials.

• The kinetic energy is transformed into thermal energy in the brake materials.

As the brakes slow the vehicle, they heat up.

What is the ability to do work called?

• Force
• Acceleration
• Energy
• Momentum

• Energy

Energy enables an object to exert a force through a distance.

What is a unit of work called?

• Newton (N)
• Meter (m)
• Joule (J)
• Watt (W)

• Joule (J)

Work is force (N) times displacement (m), which is measured in joules (J).

What does work always result in?

• An increased ability to do work
• The loss of energy
• An increase in an object’s speed
• The transfer of energy from one object or place to another

• The transfer of energy from one object or place to another

An object doing work has given energy to something else, so the object doing work now has less ability to do additional work.

What is the energy stored in a compressed spring called?

• Electromagnetic energy
• Kinetic energy
• Thermal energy
• Elastic potential energy

• Elastic potential energy

If released, the compressed spring can exert a force through a distance and do work.

Which action would increase an object’s kinetic energy the most?

• Doubling its speed
• Maintaining a constant velocity
• Bringing it to a complete stop
• Reversing its direction of motion

• Doubling its speed

Kinetic energy depends on speed.

If a car’s speed is tripled, how will the kinetic energy change?

• It will decrease.
• It will increase.
• It will not change.
• It will be cut in half.

• It will increase.

Kinetic energy depends on the square of the speed.

If a rock is raised to twice its original height, how will the gravitational potential energy change?

• It will not change.
• It will decrease.
• It will increase.
• It will be cut in half.

• It will increase.

Increasing the height will increase the gravitational potential energy of the rock.

What is thermal energy that is transferred called?

• Kelvins
• Heat
• Temperature
• Work

• Heat

Heat is the transfer of thermal energy due to a temperature difference.

When a toy dart launcher is used, which type of energy is the potential energy stored in the compressed spring converted to the dart?

• Chemical potential
• Electromagnetic
• Kinetic
• Thermal

• Kinetic

The stored elastic potential energy of the spring is converted to the toy dart’s energy of motion.

When a car’s brakes lock its wheels and cause the car to slide, which effect does the frictional force between the wheels and ground have on the energy of motion of the car?

• The energy of motion becomes chemical potential energy.
• The energy of motion becomes kinetic energy.
• The energy of motion becomes gravitational potential energy.
• The energy of motion becomes thermal energy.

• The energy of motion becomes thermal energy.

Work done by the frictional force causes the tires and ground to heat up. The ability to do this work comes from the kinetic energy of the car.

In which situation would thermal energy be transferred from the given object to the surroundings? (Ignore the effects of friction.)

• A hot hard-boiled egg placed in a bowl of cold water
• A stereo speaker causing the floor to vibrate
• A roller coaster car rolling down the track
• A waterfall causing a mill wheel to turn

• A hot hard-boiled egg placed in a bowl of cold water

The thermal energy of the egg is transferred to the cold water.

Plants convert sunlight into useful energy that is stored in the form of carbohydrates (a process called photosynthesis). Which energy conversion describes this process?

• Gravitational potential energy to chemical potential energy
• Electromagnetic energy to kinetic energy
• Electromagnetic energy to chemical potential energy
• Chemical potential energy to electromagnetic energy

• Electromagnetic energy to chemical potential energy

Plants convert sunlight into a carbohydrate form that can be used later, even by an animal that eats the plant.

What is true of the law of conservation of energy?

• An object’s energy remains constant.
• Energy can sometimes be destroyed.
• Energy can only be transferred, not converted into a different form.
• The total energy of the universe remains constant.

• The total energy of the universe remains constant.

Energy can be transformed into another energy type, but the total remains the same.

In the figure below, a thin rope is hung from the ceiling and a small ball is attached at the other end of the rope. (This configuration is called a pendulum.) Next, the ball is displaced to point A and let go. As the ball moves, it passes, in this order, through points B, and C, then again points B and A, and so on. Answer the questions below. After submitting, select "Show Answer" to see the correct response.

Which point represents the equilibrium position of the ball?

• C
• B
• A

• B

What does the ball represent?

• A propagation
• An oscillating object
• A wave

• An oscillating object

What is a repeating disturbance that transports energy from one place to another called?

• A wave
• A medium

• A wave

A wave is a disturbance that transfers energy from one place to another.

What is the material through which a mechanical wave travels called?

• An oscillation
• A medium

• A medium

A medium is a material through which a wave travels.

What can a mechanical wave not travel through?

• A medium
• A vacuum

• A vacuum

A mechanical wave cannot travel through a vacuum.

Which type of waves do not require matter to propagate?

• Electromagnetic
• Mechanical
• Water

• Electromagnetic

Water waves require matter to propagate.

Why can sound waves not travel in a vacuum?

• The vacuum consists of closely spaced particles that can stop sound waves.
• They are mechanical waves.
• They are electromagnetic waves.

• They are mechanical waves.

Sound waves are mechanical waves, which means they cannot travel through a vacuum.

In which type of wave does matter in the medium oscillate in the same direction the wave travels?

• Transverse
• Longitudinal
• Ocean
• Electromagnetic

• Longitudinal

In longitudinal waves, matter in the medium oscillates in the same direction the wave travels.

What is the region of a longitudinal wave where particles are far apart called?

• Equilibrium
• Compression
• Expansion

• Expansion

This is a region of expansion.

What does a wave transfer from one place to another?

• Energy but not matter
• Matter but not energy
• Neither energy nor matter
• Both matter and energy

• Energy but not matter

A wave transfers energy but not matter from one place to another.

A duck is floating on the surface of a lake. When a wave passes through the water, what happens to the duck?

• It will not move, but the water around it will move.
• It will move up and down, but it will return to approximately the same spot after the wave passes.
• It will be carried away with the wave to a different spot.

• It will move up and down, but it will return to approximately the same spot after the wave passes.

The duck will oscillate up and down about its original position.

A transverse wave is traveling from your left to your right. How do the particles of the medium move?

• From left to right only
• Both to the left and to the right
• Both up and down
• Downward only

• Both up and down

In a transverse wave, particles travel perpendicular to the direction of the wave.

A wave is transferring energy from north to south. The particles of the medium are oscillating in northward and southward directions. What is this is an example of?

• A longitudinal wave
• A transverse wave

• A longitudinal wave

In a longitudinal wave, particles travel parallel to the direction of the wave.

While stepping through the simulation, observe the motion of a green dot. What does it do?

• It moves horizontally with the wave.
• It does not move horizontally with the wave.

• It does not move horizontally with the wave.

The particle does not move horizontally with the wave.

Because the green dot moves perpendicular to the direction of the wave, which type of wave is this?

• Longitudinal
• Transverse

• Transverse

The particle moves perpendicular to the wave, which is the characteristic of a transverse wave.

While stepping through the simulation, when you increase the frequency, what happens to the wavelength?

• It becomes longer.
• It becomes shorter.

• It becomes shorter.

The horizontal distance from the crest of one peak to the crest of the next peak gets smaller and the wavelength gets shorter.

When the frequency of the wave increases, what happens to the amplitude?

• It decreases.
• It stays the same.
• It increases.

• It stays the same.

The amplitude of the wave does not depend on the frequency.

What is the horizontal distance from one crest of a transverse wave to the next crest called?

• Wavelength
• Amplitude
• Wave speed
• Frequency

• Wavelength

This distance is called wavelength.

What is the number of wavelengths that pass by a given point each second called?

• The wave's frequency
• The wave's speed
• The wave's amplitude
• The wave's period

• The wave's frequency

The frequency of a wave tells how many wavelengths pass by a fixed point each second.

What is the highest point of a transverse wave called?

• Crest
• Trough
• Amplitude
• Frequency

• Crest

What is the lowest point of a transverse wave called?

• Trough
• Crest
• Frequency
• Amplitude

• Trough

What is the maximum vertical distance between an equilibrium and the crest of a wave called?

• Period
• Trough
• Amplitude
• Wavelength

• Amplitude

Amplitude is the maximum vertical distance between an equilibrium and the adjacent crest of a wave.

What is the time it takes for one full oscillation of a particle in a medium?

• Frequency
• Wave speed
• Period
• Amplitude

• Period

Period is the time for one full oscillation of a particle in a medium.

Which part of the EM spectrum has the highest frequency?

• Visible light
• Radio waves
• X-rays

• X-rays

Which part of the EM spectrum has the highest energy?

• Visible light
• Ultraviolet radiation
• Infrared light

• Ultraviolet radiation

Which part of the EM spectrum has the longest wavelength?

• Radio waves
• Visible light
• Gamma rays

• Radio waves

Which color has the longest wavelength?

• Red
• Violet
• Orange
• Blue

• Red

Which color has the shortest wavelength?

• Violet
• Red
• Orange
• Blue

• Violet

How much of the EM spectrum is visible to the human eye?

• Only a small part
• All of it
• Most of it
• None of it

Only a small part

Which color has the highest energy?

• Green
• Yellow
• Blue

• Blue

Which type of electromagnetic radiation has the lowest relative frequency?

• Visible
• Ultraviolet
• X-ray
• Microwave

• Microwave

Which type of EM radiation would alert emergency personnel of a patient’s condition while the ambulance is still on the way?

• infrared radiation
• radio waves
• gamma rays
• visible light

• radio waves

Which type of EM radiation would detect an approaching tropical storm?

• visible light
• microwaves
• infrared radiation
• ultraviolet radiation

• microwaves

What is the region where the air pressure is lower than usual?

• Sound
• Expansion
• Wave
• Compression

• Expansion

An expansion is a region where the air pressure is lower than usual.

In which region have the particles been pushed closer together?

• Sound
• Compression
• Expansion
• Wave

• Compression

A compression is a region where the air particles have been pushed closer together.

When people say that the sound produced by a guitar string is a mechanical wave and not an electromagnetic wave, what do they mean?

• The sound wave can travel through a vacuum.
• A medium is needed for the sound wave to transfer energy.
• Air molecules move perpendicularly to the direction of wave propagation.
• Air molecules oscillate about their equilibrium positions.

• A medium is needed for the sound wave to transfer energy.

A mechanical wave needs a medium to transport its energy from one place to another.

How does the speed of a sound wave through a piece of glass compare to its speed through air?

• it is less
• it is the same
• it is greater

• it is greater

Sound waves move faster in glass than they do in air.

How does the speed of an electromagnetic wave through a piece of glass compare to its speed through air?

• it is less
• it is the same
• it is greater

• it is less

Electromagnetic waves move slower through a piece of glass than they do in air.

While walking on the surface of the moon, which waves do astronauts need to use to talk to each other?

• Sound waves
• Radio waves

• Radio waves

Radio waves are a type of electromagnetic waves. As such, they can propagate through the vacuum on the moon’s surface.

Why can astronauts easily converse inside the spaceship without any equipment, just like on Earth?

• because there are air particles in the spaceship
• because the astronauts are closer to each other than they are on the moon's surface

• because there are air particles in the spaceship

Sound waves in the spaceship can travel through air, just like they can on Earth.

In which situation can a sound wave propagate?

• If the medium is in a vacuum
• If the medium is water
• If the medium is air
• If particles of a medium are present

• If particles of a medium are present

A sound wave can only propagate if there are particles present. Sound waves cannot travel in a vacuum.

What accurately describes a sound wave?

• It is a transverse wave.
• It is a disturbance that moves through a medium away from the source of sound.
• It is both the motion of particles and a disturbance away from the source of sound.
• It is the motion of particles of the medium away from the source of sound.

• It is a disturbance that moves through a medium away from the source of sound.

A sound wave is a disturbance that moves through a medium away from the source of sound.

What is the term for the horizontal distance after which a wave repeats itself in space?

• Amplitude
• Wavelength

• Wavelength

The horizontal distance after which a wave repeats itself in space is called the wavelength.

You and a friend are holding a coiled spring stretched between the two of you. If you push your end toward your friend and then pull it back toward you, what type of wave will be created in the coiled spring?

• A longitudinal wave
• A transverse wave

• A longitudinal wave

A longitudinal wave will be created.

What are regions where the particles of a medium are farther apart called?

• Expansions
• Compressions

• Expansions

Regions where the particles of a medium are farther apart are called expansions.

What is a sound wave a propagation of?

• Wavelengths and expansions
• Wavelengths and compressions
• Compressions and expansions

• Compressions and expansions

A sound wave is a propagation of compressions and expansions.

In an old cowboy movie, a cowboy presses his ear to the ground, listening for the sound of approaching horse hooves. Why does the cowboy listen through the ground and not the air?

• Sound waves are affected by temperature.
• Sound waves travel faster through the ground.
• Sound waves are louder through the air.

• Sound waves travel faster through the ground.

Sound waves travel faster through the ground.

Which statement about light is correct?

• Light is not a wave.
• Light travels more slowly than sound in air.
• Light travels faster than sound.

• Light travels faster than sound.

Light is not slower than sound in air.

Which frequency does a shorter wavelength correspond to at constant speed?

• Higher frequency
• Lower frequency

• Higher frequency

A shorter wavelength corresponds to higher frequency.

While listening to someone playing a piano, you observe that when they hit a key gently, the sound is soft. When they hit the same key again a little harder, the sound is louder. What part of the sound wave increases as the sound that the piano produces becomes louder?

• Amplitude
• Wavelength

• Amplitude

Loudness is not related to wavelength.

Which statement describes amplitude?

• Amplitude is the distance between two adjacent crests.
• Amplitude is the distance between the equilibrium and trough.
• Amplitude is the distance between the crest and the trough.

• Amplitude is the distance between the equilibrium and trough.

What are radio waves commonly used for?

• Medical equipment
• Communication
• Disease treatment

• Communication

Radio waves are commonly used for communication.

Why do warm objects, such as humans and warm-blooded animals, stand out on thermal images against cooler backgrounds?

• Visible light
• X-rays
• Infrared radiation

• Infrared radiation

They emit infrared radiation.

Which property of a sound wave determines its loudness?

• Frequency
• Wavelength
• Amplitude

• Amplitude

Loudness of a sound wave is determined by its amplitude.

Which property of a sound wave determines pitch?

• Frequency
• Wavelength
• Amplitude

• Frequency

Pitch of a sound wave is determined by its frequency.

What is the most energetic radiation?

• Radio waves
• Infrared radiation
• Gamma rays

• Gamma rays

Gamma rays are the most energetic radiation.

What is the most penetrating radiation?

• Ultraviolet
• Microwave
• X-ray

• X-ray

X-rays are the most penetrating.

Suppose you produce a wave that travels along a long coiled spring by repeatedly moving the end of the spring back and forth along the direction of the spring. If you increase the number of times you move the end of the spring back and forward per second, but the speed of the wave stays the same, what increases?

• The wavelength
• The frequency
• The amplitude

• The frequency

An increase in the number of vibrations that pass through a point per second is an increase in frequency.

What determines the amount of energy a sound wave carries from a loudspeaker to a listener’s ear?

• Wavelength
• Amplitude
• Direction
• Frequency

• Amplitude

The energy carried by a wave is directly proportional to the square of its amplitude.

Which type of electromagnetic radiation has the highest frequency?

• Gamma rays
• Blue light
• Radio waves
• Infrared

• Gamma rays

Gamma rays have the highest frequency.

What are microwaves commonly used for?

• Medical imaging
• Tumor treatment
• Reading illumination
• Cell phone communication

• Cell phone communication

Cell phone communication relies on radio signals in the microwave range.

Which kind of electromagnetic radiation is commonly used for controlling air traffic by locating planes?

• Ultraviolet
• X-rays
• Visible light
• Radio waves

• Radio waves

Radar uses radio signals reflected from airplanes to locate their positions, and this is supplemented by radio communications from the aircraft.

Which characteristic distinguishes a longitudinal wave from a transverse wave?

• The amplitude of the wave’s vibration
• The direction of the wave’s vibration
• The frequency of the wave’s vibration
• The speed at which the wave travels

• The direction of the wave’s vibration

A transverse wave’s displacement is perpendicular to the direction of the wave, while a longitudinal wave’s displacement moves in the direction the wave travels.

When one end of a long rope is secured in a stationary spot and you move the other end of the rope up and down, you will create waves in the rope. Those waves carry energy. How is the energy that is carried along the length of the rope a wave?

• A longitudinal compression wave moves down the rope.
• Vibrations in the air and surroundings carry the energy of the rope.
• The entire rope moves back and forth together.
• The waveform travels along the rope without each small segment of rope moving very far.

• The waveform travels along the rope without each small segment of rope moving very far.

The energy is being transferred by the rope, not by its surroundings.

How does a sound wave carry energy from a loudspeaker to the ear of the listener?

• The vibrating molecules move from the speaker to the ear of the listener.
• The pattern of compressions travels; the air itself remains in about the same place.
• Air currents move with the sound to carry the vibrating molecules to the listener.

• The pattern of compressions travels; the air itself remains in about the same place.

There is no long-range motion of matter in the wave. The wave pattern carries the energy.

A difference in which of these characteristics distinguishes radio waves from X-rays?

• Wavelength
• Speed
• Amplitude
• Ability to travel in a vacuum

• Wavelength

Radio waves have much longer wavelengths and much lower frequencies than X-rays.

If an electromagnetic wave’s wavelength is equal to the diameter of Earth, which kind of electromagnetic wave is it?

• Microwave
• Gamma ray
• X-ray
• Radio wave

• Radio wave

Radio waves have the longest wavelengths.

If you are told the wavelength of the light emitted by a laser, what could you infer about that light?

• Its color
• Its intensity
• Its speed in a vacuum
• Its amplitude

• Its color

Each wavelength of light corresponds to a specific color.

Which set correctly lists colors of light in order of increasing wavelength?

• Blue, green, red
• Blue, red, green
• Red, blue, green
• Red, green, blue

• Blue, green, red

Of the colors listed, red light has the longest wavelength.

Electromagnetic radiation travels as waves, and the amount of energy it delivers when absorbed by matter or the damage it can cause depends on its wavelength. Which kind of light delivers the most energy and is the most damaging?

• X-rays
• Radio waves
• Microwaves
• Infrared

• X-rays

X-rays have the shortest wavelength listed and, therefore, deliver the most energy when absorbed by an atom.

Which kind of electromagnetic radiation is likely to cause a nasty sunburn if you do not use sunscreen at the beach?

• Radio waves
• Infrared
• Visible light
• Ultraviolet

• Ultraviolet

UV-B has the most energy and can cause sunburn.

Which statement describes sound waves?

• Sound is a traverse wave.
• Sound is a longitudinal wave.
• Sound can travel in a vacuum.

• Sound is a longitudinal wave.

Light is a transverse wave, and sound is a longitudinal wave.

Which statement explains why it might take several seconds after lightning strikes before thunder is heard?

• Light has more energy than sound.
• Light travels in a vacuum.
• Light is faster than sound.

• Light is faster than sound.

The light from the lightning reaches the distant observer much sooner than the sound.

Which wave from the list below is known to require a medium to travel?

• electromagnetic waves
• sound waves
• elastic waves
• coil waves

• sound waves

Sound waves are mechanical waves and require a medium to travel.

Which wave from the list below has the greatest speed?

• elastic waves
• coil waves
• electromagnetic waves
• sound waves

• electromagnetic waves

Electromagnetic waves travel at the greatest speed.