Question

An object of Mass 40 kg is raised to a height of 5m above the ground what is its potential energy? If the object is allowed to fall, find its kinetic energy when it is half way down.

Answer 1

Mass m = 40 kg.
height h = 5 m.
Potential energy PE = mgh = 40 × 9.8 × 5 = 1960J.
KE at half way down = PE at halfway down = \(mg\frac{h}{2}\)
= 40 × 9.8 × \(\frac{5}{2}\) = 980 J.