Question

A man of 10 kg is dropped from a height of 50 m find its kinetic energy

Answer 1

Gravitation Potential Energy (GPE) before drop = Maximum Kinetic Energy (KE) 

Mass = 10kg
Height = 50m
Gravity = 9.8m/s^2 

GPE = mgh 
GPE = 10×50×9.8
GPE = 490 joules

Gravitation Potential Energy (GPE) before drop = Kinetic Energy (KE) at moment of impact
Therefore at the exact moment of impact the a man will have a Kinetic Energy of 490 joules. 

As an object is about to drop, it has 100% Gravitation Potential Energy, as it drops, that Gravitation Energy will be transferred to Kinetic Energy, which is why the GPE at the top will equal the KE at the bottom.
hope it helps u....

Answer 2

>>Mass of the body, m= 10kg.

>>hight from which it drops, h= 50m.

>> kinetic energy of the body, K. E =?

>>here P.E = K.E.,,,

----> K.E = mgh

----- K.E = 10kg × 9.8× 50m
= 4900J.