# Question

Automobiles used to have firm steel bumpers for safety. Today auto bumpers are made out of materials that crumple or collapse on sufficient impact. Why is this?

## Answer to relevant Questions

Two balls of equal mass collide head on in a completely inelastic collision and come to rest. (a) Is the kinetic energy conserved? (b) Is the momentum conserved? Explain. Explain the difference for each of the following pairs of actions in terms of impulse: (a) A golfer’s long drive and a short chip shot; (b) A boxer’s jab and a knockout punch; (c) A baseball player’s bunting action ...Suppose the billiard ball in Fig. 6.31 approaches the rail at a speed of and an angle of 60o, as shown, but rebounds at a speed of 10 m/s and an angle of 50o. What is the change in momentum in this case? The linear momentum of a runner in a 100-m dash is 7.5 x 102 kg ∙ m/s. If the runner’s speed is 10 m/s, what is his mass? A one-dimensional impulse force acts on a 3.0-kg object as diagrammed in Fig. 6.32. Find (a) The magnitude of the impulse given to the object, (b) The magnitude of the average force, and (c) The final speed if the object ...Post your question

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