A motor car running at the rate of 7m//s can be stopped by brakes in 10m. Prove that the total resistance to the motion when the brakes are on is one-fourth of the weight of the car.

A motor car running at the rate of 7m//s can be stopped by brakes in 1

1.	A motor car running at the rate of 7m//s can be stopped by brakes in 10m. Prove that the total resistance to the motion when the brakes are on is one-fourth of the weight of the car.
Answer» Solution :`a=v^(2)-U^(2)//2s=-7^(2)//2xx10m//s^(2)`. `MU=ma//MG=-49/20xx9.8=-1//4`. Resistance = `mu mg =mg//4`