Gravitational potential energy

Energy gained by lifting

Lifting an object transfers energy to the gravitational potential store of the object–Earth system.

The gain depends on mass, gravitational field strength and the vertical height gained.

Use the given value of g

Always use the value of g given in the question. Our examples use 10 N/kg to keep the arithmetic clear.

Worked example

A 3 kg object is lifted 2 m. Use g = 10 N/kg.

Height means the vertical change, not the total distance along a ramp.

Challenge · energy during a fall

If air resistance is negligible, a loss of gravitational potential energy becomes a gain in kinetic energy.

To find height: h = Eₚ / (mg). To find mass: m = Eₚ / (gh).