Q: A block of mass ‘ m ‘ initially at rest is dropped from a height ‘ h ‘ on to a spring of force constant K. The maximum compression in the spring is x , then

(a) $ m g h = \frac{1}{2} k x^2 $

(b) $ m g (h+x) = \frac{1}{2} k x^2 $

(c) $ m g h = \frac{1}{2} k (x + h)^2 $

(d) $ m g( h + x) = \frac{1}{2} k (x+h)^2 $

Ans: (b)