Gravitational Potential

• Gravitational potential energy


  The energy stored in an object due to its position above the Earth's surface, due to the force of gravity acting on the object
• Gaining gravitational potential energy


  1. Using chemical energy in muscles to lift an object

  2. Storing gravitational potential energy in the object

  3. Releasing gravitational potential energy as other forms of energy when the object falls
• Equation for gravitational potential energy


  Gravitational potential energy (in Joules) = Mass (in kg) x Gravitational field strength (in N/kg) x Height (in m)
• Sample question


  • A crane lifts a 75 kg mass a height of 8 m. The gravitational field strength is 9.8 N/kg.
  • Gravitational potential energy = 75 kg x 9.8 N/kg x 8 m = 5,880 J
• Practice question


  • A ball with a mass of 500 g is lifted onto a shelf 1.5 m above the ground.
  • Gravitational potential energy = 0.5 kg x 9.8 N/kg x 1.5 m = 7.35 J
• The equation for gravitational potential energy is not given in the exam, so it must be memorised