A 1200kg car going 25m/s is brought to a stop using its brakes. Assuming that a total of approximately 20kg of iron in the brakes and wheels absorbs the heat produced by friction.

Question

A 1200kg car going 25m/s is brought to a stop using its brakes. Assuming that a total of approximately 20kg of iron in the brakes and wheels absorbs the heat produced by friction.
What was the car’s original kinetic energy and after the car has stopped, what is the change in temperature of the brakes and wheels?

bobpursley · Answer

Iniital KE=1/2 m v^2 heat in the stopping process: Initial KE massiron*specificheatiron*(deltaTemp)=heat solve for deltatemp