How are the movements of an object restricted in motion in one direction/straight line motion?
It's restricted to moving along a single axis
What is position?
The location of an object in space relative to another point
When coordinates are used to describe position what is the reference point?
The origin (0,0)
True or false, origins are fixed points.
False, anything can be the reference point used as an origin
What is displacement?
A quantity that expresses a difference in position
What is the symbol used to denote position?
x (lowercase X)
What is the mathematical description for displacement?
delta x = xf - x0
What is distance?
Total path length
What is the symbol used to denote distance?
d (lowercase D)
Distance travelled is always (+/-) but delta x is not.
+
What is the difference between displacement and distance?
Displacement is path-independent, it is only the distance between the start and end point. The length of the path does not matter to displacement, but the length of the path is what is measured in distance.
2 people running collide, at the time of collision they must have the same...
- Position
- Distance travelled
- Displacement
- all
- none
1. Position
What are the two components to a vector?
The numerical one and the directional one
50 km/h is not a vector. What is it missing?
A direction.
Ex. 50 km/h north or 50 km/h up or 50 km/h left
How are vectors represented graphically?
An arrow pointing in the appropriate direction
For a 1D vector (think of straight line motion), direction is determined exclusively by _____________.
sign
Whether a vector is negative or not, the _____________ is always positive.
Magnitude
How many different terms are associated with velocity?
4
What is the symbol for time in math?
t (lowercase T)
What is average velocity? (mathematically and in words)
vav=delta x/delta t=Displacement/change in time
vav describes how quickly an object changes position over a time interval
What is instantaneous velocity? (in words)
Velocity at a specific point in time, not over a time interval.
What is average speed? (mathematically and in words)
A scalar quantity representing the distance travelled over a change in time
sav=d/delta t
What is instantaneous speed and what is its symbol?
The speed (v) at a specific point in time; the magnitude of the velocity vector
What do speedometers in cars measure? Explain.
Instantaneous speed. The speedometer measures distance travelled (not displacement) over time at a specific point in time.
Differentiate uniform to non-uniform motion.
uniform motion is a constant velocity while non-uniform motion implies that velocity is changing
Uniform velocity implies that neither _______________ nor _______________ are changing.
Speed nor direction
How quickly velocity is changing is described by what? (name and symbol)
acceleration (a)
Describe average acceleration mathematically.
aav=change in v (velocity)/change in t
If a is constant then a=______, and vf is given by ___________________.
aav, vf=v0+at
What are the common units for acceleration?
m/s2, can be thought of like (m/s)/s
If I tell you than an object's velocity is 0 at t=1s and ask you for its acceleration, what information are you missing?
A change in time and a change in velocity.
If acceleration is constant how can vav be expressed mathematically?
vav=(v0+vf/2)
How can you tell if an object is speeding up or slowing down by looking at its v and a?
If an object is speeding up v and a will have the same sign (positive or negative), but if an object is slowing down they will have different signs.
Ex. v=+5 m/s and a=+1 m/s2 means speeding up
but... v=+5 m/s and a =-1m/s2 means slowing down
What dos the variable x represent?
displacement
What does the variable v represent?
velocity
What does it mean for v and a if motion is uniform?
v is constant and a is 0
How many unknown variables can you have per equation? How many equations do you need if you don't know 3 variables?
1 per equation, 3 equations
When you take the square root of a number, how many answers do you get?
Two, one positive, the other negative
On a position vs time graph how will uniform motion appear?
Linear
On a position vs time graph the slope connecting points a and b is the _____________ _____________ over the time interval from a to b.
average velocity
On a position vs time graph how will non-uniform motion appear?
curved (acceleration is not 0, it is changing positively or negatively)
What is a tangent line?
The slope at a given point in a curved line
On a velocity vs time graph, if __________________ is constant then you will have your change in time be equal to your velocity
acceleration
What is displacement on a velocity vs time graph?
The area under a specified change in t and v
Ex. from t=1 to t=3
Objects thrown or dropped will accelerate due to what?
Gravity
Do all objects in free fall accelerate at the same rate regardless of mass?
Yes
For an object on free fall how may acceleration be represented (as an equation)
a = -g, where g is a positive scalar
For obejcts in free fall that have been tossed up upon release what happens momentarily at their maximum heights?
They stop moving
How is motion in 2D different from 1D?
Motion happens on a surface as opposed to on a straight line
When adding vectors graphically (by drawing them out) how do you align them?
From tip to tail
When adding vectors, does the order you do them in matter?
No
When subtracting vectors does the order you do them in matter?
Yes
When multiplying vectors by a scalar (a number without direction) only the _______________ changes (unless the scalar was negative)
magnitude
What are unit vectors?
vectors with a magnitude of 1
longer vectors can be expressed by _____________ a unit vector by a scalar
multiplying
Finding the components of a vector is often referred to as ______________________ it.
resolving
What is polar form?
When a vector is described using a magnitude and an angle