AQA GCSE Gravitational potential energy
Gravitational potential energy is the energy stored in an object at height.
Depends on:
Mass of object
Gravitational field strength
Height of object
The man on the left is lifting the box, from the ground up to his colleague. The man is doing work (transferring energy mechanically) from his chemical energy store to the gravitational potential energy store of the box.
This means that if 100J of work is done, the gravitational potential energy store increases by 100J
Practice questions (assume g to be 9.8N/kg on Earth)
1. A 1.5kg book is placed on a shelf 2.5m from the ground. Calculate the gravitational potential energy of the book
2. A tennis ball of mass 200g is resting on a table 1.25m from the ground. Calculate the gravitational potential energy of the tennis ball.
3. Use the image below to answer the following question.
The ball of mass 0.5kg falls from the higher shelf to the lower shelf.
Calculate the change in gravitational potential energy when the ball falls.
4. When a rock is thrown upards at its maximum height it has a gravitational potential energy of 56kJ and it is 250cm above the ground. Calculate the mass of the rock.