Work, Energy and Power

State the equation for work done.

Work done = force x distance in the direction of the force

State what is meant by work done.

Energy transferred when a force moves an object

State 2 different units that can be used for work done.

J or Nm

State the equation when work is done at an angle.

Work done = force x distance x CosX

Which component of the force does work?

The component that is parallel to the motion

State how to calculate work done when the force is changing over time.

Change in work done = Force x change in distance

State what is meant by gravitational potential energy.

The energy of an object due to its position relative to ground level

State the equation for work done raising an object.

Work done = force x change in height

State the equation for efficiency.

Efficiency = useful output / total input

When does an object have elastic potential energy?

When it is stretched or compressed

State the relationship between GPE and KE when an object is dropped.

GPE lost = KE gained

State what is meant by power.

Rate of energy transfer

State the equation for power.

Power = Work done / time

State how to calculate change in elastic potential energy.

Change in EPE = average force x distance

State the equation for engine power.

Engine power = force x velocity

State the relationship between the forward and resistive forces acting on a object with a constant velocity.

They are equal and opposite

State the equation for engine power if the object is accelerating.

Power = force x velocity + KE/GPE gained per second