Q. A stationary object at $4℃$ and weighing $3.5\ kg$ falls from a height of $2000\ m$ on a snow mountain at $0℃.$ If the temperature of the object just before hitting the snow is $0℃$ and the object comes to rest immediately $(g = 10m/s^{2})$ and (latent heat of ice $= 3.5 \times 10^{5}\ joule/s$), then the mass of ice that will melt is
A) $2\ kg$
B) $200\ g$
C) $20\ g$
D) $2\ g$
Explanation
(b) Suppose $m\ kg$ if ice melts then by using $\begin{matrix}
W \\
(Joules)
\end{matrix} = \begin{matrix}
H \\
(Joules)
\end{matrix}$
$\Rightarrow Mgh = mL \Rightarrow 3.5 \times 10 \times 2000 = m \times 3.5 \times 10^{5}$
$\Rightarrow m = 0.2\ kg = 200\ gm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.