Unit 5 and 6 Review

Unit 5 and 6 Review

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Multiple Choice

Consider the mass and velocity values of Objects A and B below. Compared to Object B, Object A has _____ the momentum.

• Two times

• One half

• Four times

• One fourth

Multiple Choice

A football player is running down the field. He has 240 kg•m/s of northward momentum. He experiences a southward impulse of 80 N•s. What is the final momentum - magnitude and direction - of the player?

• 160 kg•m/s, northward

• 160 kg•m/s, southward

• 320 kg•m/s, northward

• 320 kg•m/s, southward

Multiple Choice

In a physics demonstration, two teams of equal-mass students are placed on each of two identical carts. A student on Cart A pushes upon Cart B. Which of the following statements describes the resulting motion of the two carts?

• Cart A will remain stationary; cart B will be propelled rightward.

• Cart A will move backwards slightly; cart B will be propelled rightward with a considerably greater speed.

• Cart B will move forward slightly; cart A will be propelled leftward with a considerably greater speed.

• Cart A and Cart B will move away from each other with the same speed.

Multiple Choice

Two carts with masses of 0.5 kg and 1.0 kg are positioned next to one another on a low-friction track. A spring-loaded plunger is released, forcing the carts away from one another in an explosion. How does the force acting upon the 0.5-kg cart compare to the force that acts upon the 1.0-kg cart?

• Both carts experience the same force.

• The force on the 0.5-kg cart is twice the strength as the force on the 1.0-kg cart.

• The force on the 0.5-kg cart is one-half the strength as the force on the 1.0-kg cart.

• The force on the 0.5-kg cart is one-quarter the strength as the force on the 1.0-kg cart.

Multiple Choice

When a bug hits your car, what goes under the greatest change in momentum?

• Both the same
• The bug
• The car
• You in the car

Multiple Choice

A 7.0-kilogram cart, A, and a 3.0-kilogram cart, B, are initially held together at rest on a horizontal, frictionless surface. When a compressed spring attached to one of the carts is released, the carts are pushed apart. After the spring is released, the speed of cart B is 6.0 meters per second, as represented in the diagram below. Which cart experiences a larger average force during the explosion?

• Cart A, because it has a larger mass

• Cart A, because the spring from Cart B pushes on it

• Cart B, because it has a smaller mass.

• Each cart experiences the same average force.

Multiple Choice

A group of students perform an experiment in which Object X and Object Y have a linear collision on a horizontal, frictionless surface. Both objects have a mass of 2 kg. The data they collect is represented in the graph below. Which of the objects experiences a negative Impulse?

• Object X

• Object Y

• Both object experience a negative impulse

• Not enough information

Multiple Choice

A group of students perform an experiment in which Object X and Object Y have a linear collision on a horizontal, frictionless surface. Both objects have a mass of 2 kg. The data they collect is represented in the graph below. Which object experiences a larger Impulse during the collision?

• Object X

• Object Y

• Both object experience the same impulse

• Not enough information

Multiple Choice

A group of students perform an experiment in which Object X and Object Y have a linear collision on a horizontal, frictionless surface. Both objects have a mass of 2 kg. The data they collect is represented in the graph below. Which of the following are true about the momentum and kinetic energy of the system during the collision?

• Momentum is Conserved; Kinetic Energy is Conserved

• Momentum is Conserved; Kinetic Energy is NOT Conserved

• Momentum is NOT Conserved; Kinetic Energy is Conserved

• Momentum is Conserved; Kinetic Energy is NOT Conserved

Multiple Choice

Two objects, A and B, are held one meter above the horizontal ground. The mass of B is twice as great as the mass of A. If PE is the gravitational potential energy of A relative to the ground, then the gravitational potential energy of B relative to the ground is

• PE

• 2 PE

• PE/2

• 4 PE

Multiple Choice

As a student walks downhill at constant speed, his gravitational potential energy --

• increases and his kinetic energy increases

• increases and his kinetic energy remains the same

• decreases and his kinetic energy increases

• decreases and his kinetic energy remains the same

Multiple Choice

An object is thrown straight upward. Which graph best represents the relationship between the object’s kinetic energy and the height of the object above its release point? [Neglect friction.]

Multiple Choice

A 500-kg roller coaster starts at rest at Point A (which is 100 m above the ground) and glides down a frictionless track. Neglect friction and air resistance. When will the roller coaster be moving the slowest (other than at Point A)?

• Point B

• Point C

• Point D

• Point E

Multiple Choice

Jenny uses a spring powered launcher to shoot darts horizontally at a target. She compresses the spring 3 cm and the dart only flies halfway to the target. The next attempt she compresses the spring the maximum distance of 6 cm. How does the Kinetic Energy of the dart compare the second time compare to the first attempt?

• the same KE

• double the KE

• triple the KE

• four time the KE

Multiple Choice

The diagram to the right represents a diver’s motion from the top of a high diving board into a pool of water. At what point does the diver have the least kinetic energy and the greatest potential energy?

• 1

• 2

• 3

• 4

Multiple Choice

A toy that is used to launch small plastic spheres vertically into the air contains a spring with a spring constant k N/m. The spring is compressed a distance d when the launcher is ready to launch a plastic sphere. The toy launches the plastic sphere a height H into the air. The spring inside the toy is replaced with a new spring with spring constant 2k, how high will the toy now launch the plastic sphere?

(NOTE: Spring constant is stretchiness of the spring, so higher spring constant means the spring is less stretchy.)

• 1/2 H

• H

• 2H

• 4H

Multiple Choice

A person on a ledge throws a ball vertically downward, striking the ground below the ledge with 200 joules of kinetic energy. The person then throws an identical ball vertically upward at the same initial speed from the same point. What is the kinetic energy of the second ball when it hits the ground? [Neglect friction.]

• 200 J

• Between 200 - 400 J

• 400 J

• More than 400 J

Multiple Choice

A spring stores 40.0 joules of elastic potential energy when it is compressed 0.20 meter. How much energy will be stored when the spring is compressed by 0.1 meter? [NOTE: PE_s = 1/2 * k * x² ]

• 5 J

• 10 J

• 20 J

• 40 J

Multiple Choice

A 4 kg block sits at the top of a rough incline, as shown above. A student measures the block's velocity of 5 m/s as the it reaches the bottom of the incline. How much mechanical energy is lost as the block slides down the ramp? [Note: Energy was lost on the way down, so calculate the PE then the KE, and find the difference between them.]

• 0 J

• 50 J

• 70 J

• 120 J

Multiple Choice

In which scenario is work = 0 J ?

• Pushing a stationary wall

• Pulling a trolley car

• Pushing a book across the table

• Dropping a set of keys from a height, h.

Multiple Choice

Workers are moving a new couch into a home. They must take the couch up 3 meters of stairs. Which of the following frictionless ramps would require the least amount of effort force.

Multiple Choice

It takes 20 N of force to lift up a box a distance of 10 m. How much work is done on the box in Joules?

• 200 J

• 20.0 J

• 100 J

• 10 J

Multiple Choice

Two construction cranes are used to lift different loads of bricks the same vertical distance. The first crane lifts 800-kilograms of bricks in 20.0 seconds and the second crane lifts 1200-kilograms of bricks in 40.0 seconds. Which of the following explains which crane generated the higher power rating?

• The first crane, because it lifts a smaller mas of bricks

• The first crane, because it lifts the bricks in a shorter time

• The second crane, because it lifts a larger mass of bricks

• The second crane, because it lifts the bricks in a larger time