Consider a car of mass 1,940 kg colliding with a rigid concrete wall at a speed

Question

Consider a car of mass 1,940 kg colliding with a rigid concrete wall at a speed of 2.9 m/s (about 6 mi/h). This impact is a fairly low-speed collision, and the bumpers on a modern car should be able to handle it without significant damage to the car. The force exerted by the wall on the car's bumper is estimated to be 80,000 N. How large is the force exerted by the wall on the car bumper (Fw) compared with the weight of the car (W)?

A textbook of mass m = 2.0 kg rests at the edge of a desk of average height.

height of table .771 meters

(a) Using your estimate for h, what is the speed of the book just before it hits the floor?

(b) If h were increased by a factor of 2.5, by what factor would the speed increase?

Explanation / Answer

Weight=1940*9.8=19012N

force exerted by the wall on the car bumper (Fw) compared with the weight of the car (W)=80000/19012=4.21 times

b)t=sqrt(2hg)=3.89m/s

increase in speed by factor=sqrt(2,5)=1.58

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.