Objects have energy in the gravitational store because of their mass and their height.

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.

Weight = mass × gravitational field strength, measured in newtons.

Gravitational field strength, g, is the force per kilogram caused by a gravitational field.

The energy stored in an object due to its height above the ground.

The energy of an object in a gravitational field (dGPE=m x g x dh)

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 gravitational store if 2× the amount of work is done lifting a tray of cakes?

A basketball stuck behind the hoop, at a height of 3.0 m. 

A basketball flying through the air at a height of 2.9 m. 

A basketball falling from the roof of a sports hall, at a height of 2.8 m.

A basketball that is moving very quickly up into the air, at a height of 2.4 m.

Which of these identical basketballs has the most energy in the gravitational store?

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

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

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

What happens to the amount of energy in the gravitational store of a pile of bricks on a table if more bricks are added to double the mass?

The type of energy that is in the gravitational store. 

The type of energy an object has because it is above the ground.

The amount of energy that is in the gravitational store.

The amount of energy an object has because it is above the ground.

What is the equation for gravitational potential energy?

What is the gravitational energy of a discus of mass 2 kg moving at a speed of 8 m/s that is 9 m above the ground? (Gravitational field strength = 10 N/kg)

Which of the following properties of an object affects the amount of energy in its gravitational store?

energy is lost from the gravitational store

energy is transferred to the kinetic store

energy is transferred from the gravitational store

Why does a free–falling object accelerate downwards?

A pupil lifts a box of books off the floor then puts it back down again. 
How much work is done (compared to the first time) if the box is lifted again to 4× the height?

Which of the following is the unit of weight?

work done = mass of the onions × height of the table

work done = mass of the onions ÷ height of the table

work done = weight of the onions × height of the table

work done = weight of the onions ÷ height of the table

How would you calculate the work done lifting a sack of onions onto a table?

A hammer has a mass of 2 kg and is on Earth.

An axe has a mass of 1.5 kg and is on Earth.

A drill has a mass of 3 kg and is on the Moon.

An electric saw has a mass of 2 kg and is on the Moon.

The gravitational force on Earth is 6× greater than it is on the Moon. 
Starting with the one with the most energy, put the tools in order of decreasing energy in the gravitational store.

This lesson will soon be taken down.

The energy of an object in a gravitational field (dGPE=m x g x dh)

Lesson outcome