The decrease in the potential energy of a ball of mass $20 kg$ which falls from a height of $50 cm$ is  

An object of mass $5 \,kg$ falls from a height of $5 \,m$ above the ground. The loss of potential energy of the mass is:

How much height must an object of mass $5kg$ be lifted to have potential energy $5000J$ ?$[g=10 m/s^2]$

A fruit hanging from the top branch of a tree possesses