Question

A 1400kg car moving westward with a velocity of 15m/s collides with a utility pole and is brought to rest in 0.30sec. find the force exerted on the car during the collision.?

Answer 1

force=(mass*velocity)-(mass*velocity)/time

force=0-(-15*1400)/0.30

force=70000N

Answer 2

Answer: - 70kN

Explanation: Since the car is moving westward that is to the left it's initial velocity Vi is -15 m/s. (Take note of the negative sign.)

It's final velocity Vf is 0 m/s since the car eventually came to rest. The time taken for this change in velocity is 0.3secs.

Recall that,

Acceleration

= change in velocity/time

= {Vf - Vi}/t

={0 - 15}/0.3

= - 50m/s²

Now force exerted on the car

F = mass* acceleration

= 1400kg*-50m/s²

= -70000N

= -70kiloNewton