A 1240-kg car is traveling with a speed of 15.0 m/s. What is the magnitude of the horizontal net force that is required to bring the car to a halt in a distance of 31.8 m?

Force required is 4387 N in the opposite direction of motion.

Explanation:

We have equation of motion v² = u² + 2as

v = 0m/s, u = 15 m/s, s = 31.8 m

Substituting

0² = 15² + 2 x a x 31.8

a = - 3.54 m/s²

So, deceleration = 3.54 m/s²

Force = Mass x Acceleration

= 1240 x - 3.54 = - 4387 N

So force required is 4387 N in the opposite direction of motion.