Question

Two masses m and 2 m are dropped from heights h and 2h. On reaching the ground, which body will have a greater kinetic energy and why?

Answer 1

K.E. of first mass, m = P.E. lost by mass m = mgh 

K.E. of second mass, 2 m = P.E. lost by mass 2 m 

= 2 m × g × 2h = 4 mgh 

Therefore, mass 2 m will have 4 times greater kinetic energy on reaching the ground.