devarshi-dt-logo

Question:

An object is dropped from height h from the ground. Every time it hits the ground it loses 50% of its energy.

83h

3h

∞

53h

Solution:

Since the object loses half its energy each time it hits the ground. Hence it will rise half of the previous height each time, as potential energy at height h is given by mgh (proportional to h).Hence it will rise h/2 after the first hit, then h/4 and so on.Hence total distance traveled will beS=h+(h/2+h/2+h/4+h/4+..)=h+(h+h/2+)=h+h(1+1/2+1/4+..)=h+h(1+11ð•’µ2)= 3h