A body falls freely under gravity. Its velocity is v when it has lost potential energy equal to U. What is the mass of the body ?

Q: A body falls freely under gravity. Its velocity is v when it has lost potential energy equal to U. What is the mass of the body ?
(a) U2/v2

(b) 2 U2/v2

(c) 2 U/v2

(d) U/v2

Ans: (c)