Aqa Igcse Physics. Key Facts Chapter 5

Front 1

What happens when a force moves an object and work is done?

Back 1

Energy is transferred. Work done (J) = energy transferred (J)

Front 2

W = F x d

Back 2

Work done (J) = Force (N) x Distance moved in the direction of the force (m)

Front 3

What happens considering the transfer of energy when brakes are applied to a vehicle?

Back 3

Friction between the brake pads and the wheel discs opposes the motion of the wheel. The kinetic energy of the vehicle is transferred into energy that heats the brake pads, the wheel discs and the surrounding air.

Front 4

What is power?

Back 4

The rate at which energy is transferred

Front 5

What is the unit for power?

Back 5

watts (W), kilowatts (kW) or megawatts (millions of watts, MW)

Front 6

What is one watt?

Back 6

The rate of transfer of one joule of energy per second (J/s)

Front 7

What is the output power of a machine?

Back 7

The rate at which it does work

Front 8

P = E / T

Back 8

Power (watts) = Work done (J) / Time taken (s) = Useful energy transferred (J) / Time taken (s)

Front 9

What is gravitational potential energy?

Back 9

Energy stored in an object because of it's position in the earth's gravitational field.

Front 10

Ep = m x g x h

Back 10

Change in gravitational potential energy (J) = mass (kg) x gravitational field strength (N/kg) x change in height (m)

Front 11

What happens to the kinetic energy if the mass or the speed increases?

Back 11

The kinetic energy increases

Front 12

Ek = 1/2 m x v2

Back 12

kinetic energy (J) = half x mass (kg) x speed (m/s squared)

Front 13

What happens to elastic potential energy when the object returns to its original shape?

Back 13

It is released