Rank in order, from largest to smallest, the momenta ${\left(p_x\right)}_{\text{A}}$ to ${\left(p_x\right)}_{\text{E}}$ of the objects in FIGURE Q11.1.

FIGURE Q11.1

A 2 kg object is moving to the right with a speed of $1\text{m}\text{/}\text{s}$ when it experiences an impulse of $4\text{N}\text{s}$. What are the object’s speed and direction after the impulse?

A 2 kg object is moving to the right with a speed of $1\text{m}\text{/}\text{s}$ when it experiences an impulse of $-4\text{N}\text{s}$. What are the object’s speed and direction after the impulse?

A 0.2 kg plastic cart and a 20 kg lead cart can both roll without friction on a horizontal surface. Equal forces are used to push both carts forward for a time of 1 s, starting from rest. After the force is removed at $t=1\text{s,}$ is the momentum of the plastic cart greater than, less than, or equal to the momentum of the lead cart? Explain.

A 0.2 kg plastic cart and a 20 kg lead cart can both roll without friction on a horizontal surface. Equal forces are used to push both carts forward for a distance of 1 m, starting from rest. After traveling 1 m, is the momentum of the plastic cart greater than, less than, or equal to the momentum of the lead cart? Explain.

Angie, Brad, and Carlos are discussing a physics problem in which two identical bullets are fired with equal speeds at equal-mass wood and steel blocks resting on a frictionless table. One bullet bounces off the steel block while the second becomes embedded in the wood block. “All the masses and speeds are the same,” says Angie, “so I think the blocks will have equal speeds after the collisions.” “But what about momentum?” asks Brad. “The bullet hitting the wood block transfers all its momentum and energy to the block, so the wood block should end up going faster than the steel block.” “I think the bounce is an important factor,” replies Carlos. “The steel block will be faster because the bullet bounces off it and goes back the other direction.” Which of these three do you agree with, and why?

It feels better to catch a hard ball while wearing a padded glove than to catch it bare handed. Use the ideas of this chapter to explain why.

Automobiles are designed with “crumple zones” intended to collapse in a collision. Use the ideas of this chapter to explain why.

A golf club continues forward after hitting the golf ball. Is momentum conserved in the collision? Explain, making sure you are careful to identify “the system.”

Suppose a rubber ball collides head-on with a more massive steel ball traveling in the opposite direction with equal speed. Which ball, if either, receives the larger impulse? Explain.

Two particles collide, one of which was initially moving and the other initially at rest.

1. Is it possible for both particles to be at rest after the collision? Give an example in which this happens, or explain why it can’t happen.

2. Is it possible for one particle to be at rest after the collision? Give an example in which this happens, or explain why it can’t happen.

Two ice skaters, Paula and Ricardo, push off from each other. Ricardo weighs more than Paula.

1. Which skater, if either, has the greater momentum after the push-off? Explain.

2. Which skater, if either, has the greater speed after the push-off? Explain.

Two balls of clay of known masses hang from the ceiling on massless strings of equal length. They barely touch when both hang at rest. One ball is pulled back until its string is at $45\text{°}$, then released. It swings down, collides with the second ball, and they stick together. To determine the angle to which the balls swing on the opposite side, would you invoke (a) conservation of momentum, (b) conservation of mechanical energy, (c) both, (d) either but not both, or (e) these laws alone are not sufficient to find the angle? Explain.