Work is done whenever a force makes an object move. The amount of work done is equal to the force multiplied by distance moved in the direction of the force.

If an object is moving and has a mass, then there is energy in its kinetic store.

If two quantities are directly proportional, then as one increases, the other also increases at the same rate.

The energy an object has in its kinetic store is referred to as the object’s kinetic energy.

Calculating the energy of moving objects (KE=1/2mv2)

Combined science

In the Forces make things change unit, they will build on this knowledge to learn how to combine forces in two dimensions, how to calculate acceleration from a resultant force and how to calculate forces in collisions and explosions.

In the Measuring and calculating motion unit, pupils learnt how to measure and calculate velocity and acceleration, and how to interpret displacement-time and velocity-time graphs. 

Energy of moving objects

How much energy will be transferred to the kinetic store if three times the amount of work is done on kicking a football?

If friction and air resistance are ignored, how much energy is dissipated by a toy car moving across a table?

The amount of energy in the kinetic store does not change.

The amount of energy in the kinetic store is two times bigger.

The amount of energy in the kinetic store is four times bigger.

What happens to the amount of energy in the kinetic store of a ball if it is moving at two times the speed?

The type of energy that is in the kinetic store.

The type of energy an object has because it is moving.

The amount of energy an object has that is in its kinetic store.

The total amount of energy that a moving object has.

What is the kinetic energy of a discus of mass 2 kg moving at a speed of 8 m/s?

What is the mass of a javelin that has a kinetic energy of 72 J and a speed of 12 m/s?

Which properties of an object can be increased so it has more energy in its kinetic store?

Energy is transferred to the surroundings.

Why does a shopping trolley that has been pushed and then let go of come to a stop?

What happens to the amount of work done moving a car, if the car is pushed with the same size force for three times the distance?

Pushing a trolley forward to speed it up.

Pushing a trolley forward against friction, to keep it at the same speed.

Pushing down on a trolley as it moves forwards.

Pushing on a trolley backwards to slow it down.

In which of these situations does the applied force **not** do any work?

Work done = force of catapult × distance over which it pushes on the ball

Work done = force of catapult ÷ distance over which the ball moves

Work done = force of catapult × mass of the ball

Work done = force of catapult  ÷ mass of the ball

How would you calculate the work done by a catapult in shooting a small ball forward?

Energy in the kinetic store as the ball leaves the catapult.

Energy in the kinetic store at its highest point.

The energy in the gravitational store when the ball leaves the catapult.

Energy in the gravitational store at its highest point.

A catapult does work on a small ball to fire it vertically up into the air. What is the amount of work done on the ball equal to?

Starter Quiz