What net braking force must be applied to stop a car with a mass of 900 kg initially travelling at a velocity of 100 km/h within a straight-line distance of 50 m?

Answer 1

(Braking Force) x distance = Initial Kinetic Energy

Force times distance is work done against friction, which must equal the initial kinetic energy.

Change 100 km/h to m/s before calculating Kinetic Energy

For the Kinetic Energy formula, read my answer to your previous question.

Answer 2

200