What is the kentic energy of a 2 kg ball as it falls half way from a 40 meter tall building

392

Explanation:

According to the law of conservation of energy, energy cannot vanish, so the lost potential energy must be converted into another form of energy (in this case, Kinetic Energy).

(mass*g*height) - (mass*g*halfway height) = (2*9.8*40) - (2*9.8*20)

784-392=392

This makes sense because since the rock has fallen halfway, half of its potential energy has become kinetic energy. Once the rock reaches a height of 0 Meter, all of its potential energy will be kinetic energy.