Physics Test

Each croquet ball in a set has a mass of 0.50 kg. The green ball travels at 10.5 m/s and strikes a stationary red ball. If the green ball stops moving, what is the final speed of the red ball after the collision?

10.5 m/s

Which of the following has the greatest momentum?

A tortoise with a mass of 275 kg moving at a velocity of 0.55 m/s

A moderate force will break an egg. Using the concepts of momentum, force, and time interval, explain why an egg is more likely to break when it is dropped on concrete than if it is dropped on grass.

Because the grass extends the time over which the force is applied on the egg

Why is the sound produced by a collision evidence that the collision is not perfectly elastic?

Because the sound is evidence that energy is lost during the collision

A 20 kg shopping cart moving at a velocity of 0.5 m/s collides with a store wall and stops. The momentum of the shopping cart...

Decreases

Two objects move separately after colliding, and both the total momentum and total kinetic energy remain constant. Identify the type of collision.

Elastic

After colliding, objects are deformed and lose some kinetic energy. Identify the type of collision.

Inelastic

Almost all collisions in the everyday world are of what type?

Inelastic

Two balls of dough collide and stick together. Identify the type of collision.

Inelastic

Two objects stick together and move with a common velocity after colliding. Identify the type of collision.

Inelastic

Two objects stick together and move with the same velocity after colliding. Identify the type of collision.

Inelastic

A roller coaster climbs up a hill at 4 m/s and then zips down the hill at 30 m/s. The momentum of the roller coaster...

Is greater down the hill than up the hill.

An ice skater initially skating at a velocity of 3 m/s speeds up to a velocity of 5 m/s. How does the momentum of the skater change?

It increases

On a pool table, a moving cue ball collides with the eight ball, which is at rest. Is it possible for both balls to be at rest after the collision? Use the law of conservation of momentum to explain your reasoning.

No, because one ball will have to be moving after the collision.

How can a small force produce a large change in momentum?

Over a longer period of time

A rubber ball moving at a speed of 5 m/s hit a flat wall and returned to the thrower at 5 m/s. The magnitude of the momentum of the rubber ball...

Remained the same

A force is applied to stop a moving shopping cart. Increasing the time interval over which the force is applied

Requires a smaller force

As a bullet travels through the air, it slows down due to air resistance. How does the bullet's momentum change as a result?

The bullets momentum decreases

A child with a mass of 23 kg rides a bike with a mass of 5.5 kg at a velocity of 4.5 m/s to the south. Compare the momentum of the child with the momentum of the bike.

The child has a greater momentum than the bike.

A baseball pitchers first pitch is a fastball, moving at high speed. The pitchers second pitch -- with the same ball -- is a changeup, moving more slowly. Which pitch is harder for the catcher to stop? Explain your answer in terms of momentum.

The first pitch because it is moving at a higher speed

When comparing the momentum of two moving objects, which of the following is correct?

The less massive object will have less momentum if the velocities are the same.

State, in words, the law of conservation of momentum for an isolated system.

The momentum is the same both before and after a collision.

A billiard ball collides with a second identical ball in an elastic head-on collision. What is the kinetic energy of the system after the collision compared with the kinetic energy before the collision.

Unchanged

A person sitting in a chair with wheels stands up, causing the chair to roll backwards across the floor. The momentum of the chair...

Was zero while stationary and increased when the person stood up.

A student walks to class at a velocity of 3 m/s. To avoid walking into a door as it opens, the student slows to a velocity of 0.5 m/s. Now late for class, the student runs down the corridor at a velocity of 7 m/s. At what point in this scenario does the student have the least momentum?

When avoiding the door

Two billiard balls of equal mass are traveling straight toward each other with the same speed. They meet head-on in an elastic collision. What is the total momentum of the system containing the two balls before the collision?

Zero

Two snowballs are traveling straight toward each other. One snowball has twice the mas of the other, but is moving at half the speed. The snowballs meet head-on in a perfectly inelastic collision. What is the total momentum of the system containing the two snowballs before the collision.

Zero

A 75 kg person walking around a corner bumped into a 80 kg person who was running around the same corner. The momentum of the 80 kg person...

decreased

What are the SI units for momentum?

kg m/s

The impulse experienced by a body is equivalent to the body's change in...

momentum

Which of the following equations can be used to directly calculate an object's momentum, p?

p = mv

A soccer ball collides with another soccer ball at rest. The total momentum of the balls...

remains constant

Two objects with different masses collide and bounce back after an elastic collision. Before the collision, the two objects were moving at velocities equal in magnitude but opposite in direction. After the collision...

the less massive object had gained momentum

In an inelastic collision between two objects with unequal masses,

the momentum of one object will increase by the amount that the momentum of the other object decreases

The change in an object's momentum is equal to...

the product of the force applied to the object and the time interval

Two skaters stand facing each other. One skater's mass is 60 kg, and the other's mass is 72 kg. If the skaters push away from each other without spinning...

their momenta are equal but opposite

Two swimmers relax close together on air mattresses in a pool. One swimmer's mass is 48 kg, and the other's mass is 55 kg. If the simmers push away from each other...

their momenta are equal but opposite

Which of the following equations can be used to directly calculate the change in an object's momentum?

Δp = FΔt