Question

The front 1.20 m of a 1550 kg car is designed as a "crumple zone" that collapses to absorb the shock of a collision.
(a) If a car traveling 26.0 m/s stops uniformly in 1.20 m, how long does the collision last?

cannot_evaluate
s
(b) What is the magnitude of the average force on the car?
N
(c) What is the acceleration of the car? Express the acceleration as a multiple of the acceleration of gravity.

Answer 1

(a) t = (crumple distance)/(average speed)
= 1.20 m/13 m/s = 0.092 s

(b) (force)*(crumple distance) = initial kinetic energy = (1/2) M Vo^2
Solve for the force F
F = (1/2) M Vo^2/X

OR acceleration a = Vo/t = Vo^2/(2X)
and F = M a = M Vo^2/(2X)
(same result)

(c) I already solved for a. Divide it by g to get what they want