A car has a crumple zone that is 0.80 m (80 cm) long. In this car, the distance from the dummy to the steering wheel is 0.50 m. The car has a mass of 1,600 kg and the dummy has a mass of 75 kg. At the time of the crash, the car has a speed of 18 m/s. Based on the work-energy theorem, what is the smallest possible force that the dummy could experience during the crash?

Question

An SUV crashes into a wall. The mass of the vehicle is 2,150 kg and the crumple zone rigidity is 342 kN. Assuming the safety cell is perfectly rigid, what will be the acceleration of the SUV during a crash as the crumple zone is collapsing?

please help thanks:)

Answer 1

Normally I would use momentum but since you say use wok energy then'

initial KE of dummy = (1/2) m v^2 = .5 * 75 * 18^2
the dummy stops in .5 + .8 = 1.3 meters
force * distance = work = change in Ke
so
F * 1.3 = .5 * 75 * 18^2
==========================================
F = m a
342,000 = 2,150 a

Answer 2

Damon would it be -0.159 or -159?

Answer 3

–199 kN

Answer 4

A.) -9.35 kN

C.) -159 m/s squared

Answer 5

The right answer is -9.35

Answer 6

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Thank you