A car with a mass of 1200 kg moves at 18 m/s. What braking force is needed to bring the car to a halt in 10 s?

Question

A car with a mass of 1200 kg moves at 18 m/s. What braking force is needed to bring the car to a halt in 10 s?

Answer 1

impulse is the force apply over time. Impulse change momentum of the car.

Ft = mv

F(10) = 1200(0-18)
F(10) = -21600
F = -2160

the negative means the force is opposite of the motion

Answer 2

v = v0 + at and, since it's decelerating, a is negative, so
0 = 18 - a*10 => a = 1.8 m/s² Now F = ma so
F = 1200*1.8 = 2318.4 N

HTH ☺

Doug