IGCSE Physics 1 | Motion, Forces, Energy Flashcards

A scalar quantity has magnitude(size) only and that a vector quantity has magnitude and direction.

Know that the following quantities are scalars:distance, speed, time, mass, energy and temperature.

Know that the following quantities are vectors: force, weight, velocity, acceleration, momentum, electric field strength and gravitational field strength

approximately constant and is approximately 9.8 m/s2

• Speed is the gradient of a distance-time graph
• Acceleration is the gradient of a speed-time graph
• Distance is area under a speed-time graph

change in velocity per unit of time

change in velocity / change in time

When the force of air resistance becomes equal to the force of weight, then the object stops accelerating and falls at a constant speed

Impulse = change in momentum

Impulse = force (N) x time force acts

Momentum = mass x velocity

Change in momentum = (mass(kg) x final velocity) - (mass x initial velocity)

Force = ma

mass x acceleration

KE = ½ mv²

Kinetic energy = ½ x mass x velocity²

ρ = m / V

density = mass / volume

The amount of thermal energy required to change the state of 1 kilogram of a substance from solid to liquid at its melting point, without changing the temperature.

E = mc(Δ)T

Energy = mass x heat capacity x change in temperature

Energy = mass x specific latent heat

E = mc(Δ)T

Energy = mass x heat capacity x change in temperature

force per unit mass

g = W/m

gravitational field strength (N/kg) = weight (newtons) / mass (kg)

Mass per unit volume.

Density = m/v

force per unit extension. measures the stiffness of a spring, higher the k the more stiff

k = F/x

spring constant = Force / extension

1. Align the marker to a value on the ruler with no mass added to the spring, and record this initial length of the spring
2. Add the 100 g mass hanger onto the spring
3. Record the mass (in kg) and position (in cm) from the ruler now that the spring has extended
4. Add another 100 g to the mass hanger
5. Record the new mass and position from the ruler now that the spring has extended further
6. Repeat this process until all masses have been added
7. The masses are then removed and the entire process is repeated again until it has been carried out a total of three times, and an average length is calculated

• multiply each mass by gravitational field strength, g = 9.8 N/kg, to calculate the force, F
• plot it against extension to form a force-extension graph.

• A greater mass requires a greater force when the speed and radius are constant.
• A faster-moving object requires a greater force when the mass and radius are constant.
• A smaller radius requires a greater force to keep the speed and radius constant.

The force between two surfaces that may impede motion and produce heating.

Friction (drag) acts though a liquid or a gas.

A moment is the turning effect of a force. It acts around a pivot.

moment = force × perpendicular distance from the pivot

1. Suspend the metre rule at the 50 cm mark so that it is balanced horizontally. The ruler is said to be in equilibrium. The 50 cm mark is the pivot.
2. Suspend a mass, m1, from one side of the ruler a distance, d1, from the pivot. Read the distance d1 in cm. Record in a suitable table. Record the value of mass m1 in kg in the table too.
3. Suspend a second mass, m2, from the other side of the pivot. Carefully move this mass backwards and forwards until the ruler is once more balanced horizontally. Record the distance and mass in the table too.
4. Repeat several times using different masses and distances.
5. Calculate the turning forces, F1 and F2, using W = mg.
6. Calculate the clockwise and anticlockwise moments.

The point through which the weight of an object acts.

An object will topple over if its centre of gravity is 'outside' the base, or edge, on which it balances.

1. A small hole is made at the top of the plane lamina.
2. The plane lamina is hung from this hole to allow it to pivot.
3. The plumb line is also hung from here and will fall vertically downwards.
4. A dotted line is draw along the plumb line to the mass.
5. The second hole can be made anywhere close to the edge of the shape and does not specifically need to be at the bottom.
6. The above steps are repeated.
7. The centre of gravity is where the lines cross.

The change in momentum per unit time.

F = ∆p/∆t

Resultant force = change in momentum / change in time

kinetic, gravitational potential, chemical, elastic (strain), nuclear, electrostatic and internal (thermal)

change in gravitational potential energy (J) = mass x acceleration due to gravity x change in height (m)

W = Fd = ∆E

Work done (J) = Force x displacement = Energy change (J)

(a) chemical energy stored in fossil fuels

(b) chemical energy stored in biofuels : Biofuels are derived from renewable plant materials. Similar to fossil fuels, they contain stored chemical energy that can be released through combustion which can then be used to drive turbines and generate electricity.

(c) water, including the energy stored in waves, in tides, and in water behind hydroelectric dams

(d) geothermal resources : generate steam, which drives turbines and produces electricity.

(e) nuclear fuel : Nuclear energy is obtained by splitting atoms (fission) in nuclear reactors. The energy released during this process is used to heat water, which then generates steam to drive turbines and produce electricity.

(f) light from the Sun to generate electrical power (solar cells) : using photovoltaic cells.

(g) infrared and other electromagnetic waves from the Sun to heat water (solar panels) and be the source of wind energy

when a turbine, powered by falling water, wind, or steam from boiling water, spins a generator, which converts this mechanical motion into electrical energy.

Fission: Uranium or plutonium isotope that will split when triggered by an incoming neutron.

Nuclear fusion is when two small, light nuclei join together to make one heavier nucleus. Fusion reactions occur in stars where, for example, two hydrogen nuclei fuse together under high temperatures and pressure to form a nucleus of a helium isotope. Energy is released by nuclear fusion in the Sun.

Define power as work done per unit time and also as energy transferred per unit time.

as force per unit area

Pressure = force/area

change in pressure beneath the surface of a liquid (Pascals (Pa) = density x acceleration due to gravity x change in height

a measure of the quantity of matter in an object at rest relative to the observer

a gravitational force on an object that has mass

the point on a force-extension graph where force and extension are no longer directly proportional