Gravitational Potential Energy (AQA GCSE Physics: Combined Science)

• Energy in the gravitational store of an object is defined as:

The energy an object has due to its height in a gravitational field

• This means:
  • If an object is lifted up, energy is transferred to its gravitational potential store 
  • If an object falls, energy will be transferred away from its gravitational potential store

Gravitational Potential Energy Equation

• The gravitational potential energy, E_p, of an object can be calculated using the equation:

E_p = m × g × h

• Where:
  • E_p = gravitational potential energy, in joules (J)
  • m = mass, in kilograms (kg)
  • g = gravitational field strength in newtons per kilogram (N/kg)
  • h = height in metres (m)

Gravitational Field Strength

• The gravitational field strength (g) on the Earth is approximately 9.8 N/kg
• The gravitational field strength on the surface of the Moon is less than on the Earth
  • This means it would be easier to lift a mass on the Moon than on the Earth

• The gravitational field strength on the surface of the gas giants (eg. Jupiter and Saturn) is more than on the Earth
  • This means it would be harder to lift a mass on the gas giants than on the Earth

Some values for g on the different objects in the Solar System