posted by Brittany on .
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?
(b) What is the magnitude of the average force on the car?
(c) What is the acceleration of the car? Express the acceleration as a multiple of the acceleration of gravity.
(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)
(c) I already solved for a. Divide it by g to get what they want