2.2 Conservation of energy

The law of conservation of energy states that energy may neither be created nor destroyed. Therefore the sum of all the energies in the system is a constant. Stretching an elastic band transfers chemical energy to elastic potential energy. Swinging pendulum transfers energy from gravitational potential energy to kinetic energy and back again as it swings.

 PE = mgh <---Formula

PE = mgh <----- Formula

The mass of the ball = 10kg 
The height, h = 0.2m 
The acceleration due to gravity, g = 9.8 m/s^2 
Substitute the values into the formula and you get:

PE = 19.6J (J = Joules, unit of energy)