Q. Hailstone at $0℃$ falls from a height of $1\ km$ on an insulating surface converting whole of its kinetic energy into heat. What part of it will melt $(g = 10m/s^{2})$
A) $\frac{1}{33}$
B) $\frac{1}{8}$
C) $\frac{1}{33} \times 10^{- 4}$
D) All of it will melt
Explanation
(a) Suppose $m^{'}\ kg$ ice melts out of $m\ kg.$ Then by using
$W = JQ \Rightarrow mgh = J\left( m^{'}L \right).$ Hence fraction of ice melts
$= \frac{m^{'}}{m} = \frac{gh}{JL} = \frac{9.8 \times 1000}{4.18 \times 80} = \frac{1}{33}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.