Question

A block of ice falls from certain height and completely melts. If only $\frac{3}{4}th$ of the energy is absorbed by the block, the height of the fall should be ( $L=363$ in SI units and $g=10m{s}^{-2}$)

• A. 48.4m
• B. 84.4 m
• C. 88.4 m
• D. 44.8 m

Answer 1

The correct option is A 48.4m

Amount of energy required for the ice to completely melt$=mL=m\left(363\right)$
Amount of energy absorbed by the ice block as it falls$=\frac{3}{4}mgh$
$\therefore \frac{3}{4}mgh=m\left(363\right)$
$h=\frac{\left(363\right)\left(4\right)}{\left(3\right)\left(10\right)}=48.4m$
Option A.