# A van of mass 1500 kg travelling at a speed of

Question:

A van of mass $1500 \mathrm{~kg}$ travelling at a speed of $54 \mathrm{~km} / \mathrm{h}$ is stopped in $10 \mathrm{~s}$. Assuming that all the mechanical energy lost appears as thermal energy in the brake mechanism, find the average rate of production of thermal energy in cal/s.

Solution: