A van of mass 1500 kg travelling at a speed of 54 km h^–1 is stopped in 10 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^–1.

Question

Philoid · Accepted Answer

Given:

Mass of van=1500kg

Speed=15m/s

Time taken to stop=10s

Formula used:

Mechanical energy=kinetic energi=1/2mv²

M=mass

V=velocity

So

Kinetic energy=1/2× 1500×225=168750J

Average rate of production of thermal energi=energy produced /time

=168750/10 J/s

=4017.8 cal/s

A van of mass 1500 kg travelling at a speed of 54 km h–1 is stopped in 10 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–1.