ENERGY CONSERVATION [CALCULATIONS]

If an object is dropped the Gravitational Potential Energy lost is equal to the Kinetic Energy gained. We keep problem simple by assuming there is no air resistance. If we included air resistance, the amount of Kinetic Energy gained would be less than the initial Gravitational Potential Energy as some would be lost as Heat.

This means that if we know the mass of an object and the height from which it is dropped we can work out how fast it will travelling when it hits the ground (assuming no air resistance). This is because...

Gravitational Potential Energy Lost = Kinetic Energy Gained

If the ball has a mass of 1.0 kg and is dropped from a height of 5.0m then the Gravitational Potential Energy lost as it falls is:

The velocity of the object when it hits the ground is...

Because the Kinetic Energy gained is equal to the Gravitational Potential Energy lost...