Bumpers on cars are not of much use in a collision. To see why, calculate the average force a bumper would have to exert if it brought a 1200 kg car (a so-called "compact" model) to a rest in 15 cm when the car had an initial speed of 2 m/s (about 4.5 mph). Bumpers are built with springs which compress to provide a stopping force without (hopefully) denting the metal

Answer 1

For the force required, multiply the mass by the required decleration, a.

V = sqrt(2aX)

a = V^2/(2X) = 13.3 m/s^2

M a = ___ Newtons

Answer 2

1600

Answer 3

15960