Conservation of Momentum 222

A train car has a mass of 10,000 kg and is moving at +3.0 m/s. It strikes an identical train car that is at rest. The train cars combine. What is the magnitude of the final velocity of the combined cars? 0 m/s 1.5 m/s 3.0 m/s 6.0 m/s

1.5 m/s

A basketball player passes a ball to a teammate at a velocity of 6 m/s. The ball has a mass of 0.51 kg. If the original player has a mass of 59 kg and there is no net force on the system, what is the velocity of the player after releasing the ball? Let a positive velocity be in the direction of the pass. -0.05 m/s -0.5 m/s -0.6 m/s -6 m/s

-0.05 m/s

A 50 kg boy runs and jumps with a forward velocity of 1.5 m/s into a 125 kg stationary boat. What is the final velocity of the boy/boat system? 0.43 m/s, forward 0.43 m/s, backward 1.1 m/s, forward 1.1 m/s, backward

0.43 m/s, forward

A ball has a mass of 0.25 kg and is moving to the right at 1.0 m/s. It hits a ball of mass 0.15 kg that is initially at rest. After the collision, the 0.15 kg ball moves off to the right with a velocity of 0.75 m/s. What is the final velocity of the 0.25 kg ball? 0.42 m/s to the right 0.42 m/s to the left 0.55 m/s to the right 0.55 m/s to the left

0.55 m/s to the right

In a game of pool, a 0.4 kg cue ball is traveling at +0.80 m/s when it hits a slower striped ball moving at +0.38 m/s. After the collision, the striped ball moves off at +0.62 m/s. What is the magnitude of the final velocity of the cue ball? Assume all pool balls have the same mass. 0.20 m/s 0.56 m/s 1.0 m/s 1.8 m/s

0.56 m/s

A bowling ball has an initial momentum of +30 kg m/s and hits a stationary bowling pin. After the collision, the bowling ball leaves with a momentum of +13 kg • m/s. What is the magnitude of the final momentum of the bowling pin if it has a mass of 1.5 kg? 0 kg • m/s 11 kg • m/s 17 kg • m/s 43 kg • m/s

17 kg • m/s

An empty 2,500 kg train car is headed northbound at a velocity of 5 m/s. Ahead of the first car, an empty 1,500 kg car is headed northbound on the same track at 1 m/s. The faster train bumps into the slower one, and they combine into one train. What is the velocity of the two-car train? 1 m/s 3 m/s 3.5 m/s 5 m/s

3.5 m/s

Momentum data about the same objects in the same closed system is shown below. What value should be in place of the X? 3.4 3.5 3.6 3.7

3.6

A 35-gram stainless steel ball on a track is moving at a velocity of 9 m/s. On the same track, a 75-gram stainless steel ball is moving at a velocity of -7 m/s. After colliding, the 35-gram ball moves at a velocity of -15 m/s. Assume there is no net force on the system. What is the velocity of the 75-gram ball after the collision? Round to the nearest tenth. -4.2 m/s -0.5 m/s 0.5 m/s 4.2 m/s

4.2 m/s

Two grocery carts have the same initial total momentum. The two carts collide, and now cart B has a greater final velocity. Which best describes the final total momentum of both the carts compared to the initial total momentum? It is less if cart B has a smaller mass. It is greater if cart B has a greater mass. It is the same if no external forces are added. It depends on the masses of cart A and cart B.

It is the same if no external forces are added.

A rubber bullet of mass m is fired from a rifle into a stationary block of 25 m. The bullet remains in the block and both the bullet and the block move off with a common velocity. Assume this is an inelastic collision in a closed system. Which best describes the final momentum of the bullet/block? The final momentum of the bullet/block is zero. The final momentum of the bullet/block is equal to the initial momentum of the bullet. The final momentum of the bullet/block is less than the initial momentum of the bullet. The final momentum of the bullet/block is more than the initial momentum of the bullet.

The final momentum of the bullet/block is equal to the initial momentum of the bullet.

For a movie stunt, an empty truck with a mass of 2000 kg goes 10 m/s and runs into a stopped car of mass 1000 kg. The truck then keeps moving and pushes the car along with it. If there are no other forces acting on this system, which best describes the results of the collision? The collision is perfectly elastic. Kinetic energy stays the same. The momentum after the collision is greater than the momentum before the collision. The speed of the combined vehicles is less than the initial speed of the truck.

The speed of the combined vehicles is less than the initial speed of the truck.

Two blocks are initially at rest with a compressed spring between them. When the spring is released, the 2m block moves to the left and the m block moves to the right. This represents an inelastic collision in a closed system. What best describes the blocks after the spring is released? The total energy is zero. The total momentum is zero. The momentum of the m block is zero. The momentum of the 2m block is zero.

The total momentum is zero.

In an elastic collision, ⇒ energy is conserved.

kinetic

Which equation best describes the law of conservation of momentum? pi = pf pi > pf pi < pf pi + pf = 0

pi= pf

In a lab, two identical lab carts (m = 1.0 kg) travel toward each other, each with a speed of 2 m/s. The cars collide, and one cart moves to the right with a speed of 3 m/s and the other moves left with a speed of 2 m/s. What best explains the results of the experiment? This experiment did not occur in a closed system. This proves the conservation of momentum since pi = pf . An additional mass was added to one cart, which explains the increase in speed. The increase in speed was due to the kinetic energy from one cart transferring to the other.

This experiment did not occur in a closed system.

Two carts, one of mass 2m and one of mass m, approach each other with the same speed, v. When the carts collide, they hook together. Assume that positive momentum is to the right. Which graph best represents the momentum of both carts over time, before and after the collision?

B

Two identical carts travel at the same speed toward each other, and then a collision occurs. The graphs show the momentum of each cart as a function of time, both before and after the collision. Which graph shows a perfectly inelastic collision?

B

A girl is standing still in the middle of a baseball field. The girl catches the baseball and begins to move in the same direction as the thrown ball. What type of collision is being described? inelastic, since the girl moves in the same direction as the thrown ball inelastic, since the girl moves in the opposite direction of the thrown ball elastic, since the girl moves in the same direction as the thrown ball elastic, since the girl moves in the opposite direction of the thrown ball

inelastic, since the girl moves in the same direction as the thrown ball