Question

A 500-kg car is moving at 28m/s. The driver sees a barrier ahead. If the car takes 95 meters to come to rest, what is the magnitude of the minimum average net force necessary to stop? 

(A) 47.5 N 

(B) 1400 N 

(C) 2060 N 

(D) 19600 N 

(E) 133000 N

Answer 1

Correct option (C) 2060N 

Using work-energy. W_nc = ∆K = K_f – K_i – Fd = 0 – ½ mv_f² – F(95) = – ½ (500)28².