What distance will be needed to bring an object of mass 10 kg moving at a velocity of 5 m/s to rest if a constant force of 100 N is applied to the body in the opposite direction to its motion? A car...

What distance will be needed to bring an object of mass 10 kg moving at a velocity of 5 m/s to rest if a constant force of 100 N is applied to the body in the opposite direction to its motion?

A car of mass 1200 kg travelling at 20 m/s brakes. The wheels lock and the car slides 30 m before coming to rest. What is the average frictional force bringing the car to rest?