Question

If in stopping a car of mass 800 kg by applying brakes, 4.18 kcal of heat is produced ,then what was the speed of the car before applying the breakes?

Answer 1

(mv^2)/2 = 4.18 × 10^3 × 4.184.
v^2 = 17489.12*2 / 800 = 21.8614 *2
v = 6.612 m/s^2.

This was my answer to your question :)