Physics 1301 Chapter 5, 7, & 8 Review

Suppose that we attach Velcro® to the non-magnetic ends of the two carts in the video and remove the mass bars, so that both carts have the same mass. We repeat the experiment shown in the video, and the carts stick together after they collide. If the launch cart travels at a speed v0, then how fast will the combined two-cart system travel after the collision?

0.5v0

Which of the following statements is/are true?

A person is limited in the total work he or she can do by the rate at which energy can be transformed. The SI unit of power is the watt. Power is the rate at which work is done. Power is the rate at which energy is transformed.

In the opening scenes of the prelecture video, we outlined some of the key properties of momentum. Which of the following statements are consistent with these properties?

An object's momentum is equal to the product of its mass and its velocity. Momentum is a vector quantity.

For an elastic collision, which of the following statements are true?

Momentum is conserved. Kinetic energy is conserved.

For an INELASTIC collision, which of the following statements are true?

Momentum is conserved. Kinetic energy is lost.

A motorcycle drives up a steeply inclined ramp. The work done on the motorcycle by the Earth's gravitational force is ____.

Negative

Person B does twice the work of person A, and in one-half of the time . How does the power output of person B compare to person A?

Person B has four times the power output of person A.

A crate slides up an inclined ramp and then slides down the ramp after momentarily stopping near the top. This crate is acted upon by friction on the ramp and accelerates both ways. Which statement about this crate's acceleration is correct?

The acceleration going up the ramp is greater than the acceleration going down.

A lump of putty and a rubber ball have equal mass. Both are thrown with equal speed against a wall. The putty sticks to the wall. The ball bounces back at nearly the same speed with which it hit the wall. Which object experiences the greater momentum change?

The ball experiences the greater momentum change.

When a constant force acts on an object, what does the object's change in momentum depend upon?

The change in momentum depends upon the magnitude of the force. The change in momentum depends upon the mass of the object. The change in momentum depends upon the time interval during which the force acts. The change in momentum depends upon the change in the velocity of the object.

In general, how does the coefficient of static friction compare to the coefficient of kinetic friction for the same two materials?

The coefficient of static friction is greater than the coefficient of kinetic friction.

What represents the impulse of the force in a graph of force versus time?

The impulse is equal to the area under the curve.

In a lab environment, you are investigating the impulse of a force exerted on a brick when the brick's speed is reduced from 2.5 m/s to a complete stop. First, you allow the brick to slam into a secured piece of wood, bringing the brick to a sudden stop. Second, you allow the brick to plow into a large slab of gelatin so that the brick comes to a gradual halt. In which situation is there a greater impulse of the force on the brick?

The impulse is the same in both situations.

A packing crate is sitting at rest on an inclined loading ramp. How does the magnitude of the force of static friction compare to the other forces acting on the crate?

The magnitude of the force of static friction is equal to the magnitude of the component of the weight of the crate parallel to the inclined ramp.

An object is hanging by a string from the ceiling of an elevator. The elevator is moving upward with a constant speed. What is the magnitude of the tension in the string?

The magnitude of the tension in the string is equal to the magnitude of the weight of the object.

An object is hanging by a string from the ceiling of an elevator. The elevator is slowing down while moving upward. What is the magnitude of the tension in the string?

The magnitude of the tension in the string is less than the magnitude of the weight of the object.

Which statement must be true for the momentum of a system to be conserved?

The net external force on the system is zero.

If the net work done on an object is positive, what can you conclude about the object's motion?

The object is speeding up.

If the net work done on an object is zero, what can you determine about the object's kinetic energy?

The object's kinetic energy remains the same.

While goofing off at the ice skating rink, a student takes off her shoes and places each of them on the ice. Her friend, a hockey player, then shoots a hockey puck at each shoe. The first puck immediately comes to rest after it collides with the left shoe. The second puck rebounds after it collides with the right shoe. If each hockey puck has the same incoming speed, which shoe has greater speed after the collision?

The right shoe

A freight car moves along a frictionless level railroad track at constant speed. The freight car is open on the top. A large load of sand is suddenly dumped into the freight car. What happens to the speed of the freight car?

The speed of the freight car decreases.

Which of the following statements is/are true?

The total mechanical energy of a system is constant only if conservative forces act. Mechanical energy can be dissipated to nonmechanical forms of energy.

Which of the following statements are true? Select all correct responses

The total momentum of any number of particles is equal to the vector sum of the momenta of the individual particles. The vector sum of forces acting on a particle equals the rate of change of momentum of the particle with respect to time. The total momentum of an isolated system is constant.

When a person steps forward out of a small boat onto a dock, the boat recoils backward in the water. Why does this occur?

The total momentum of the system is conserved.

Two objects are moving at equal speed along a level, frictionless surface. The second object has twice the mass of the first object. They both slide up the same frictionless incline plane. Which object rises to a greater height?

The two objects rise to the same height.

During a certain time interval, the net work done on an object is zero joules. We can be certain that ____.

the object's final speed was the same as its initial speed

Two identical cars are driving in opposite directions at the same speed. Their kinetic energies have ____

the same magnitude and sign

A graph depicts force versus position. What represents the work done by the force over the given displacement?

The work done is equal to the area under the curve.

A ball is thrown straight upward. How does the sign of the work done by gravity while the ball is traveling upward compare with the sign of the work done by gravity while the ball is traveling downward?

Work done by gravity is negative while the ball is traveling upward and positive while the ball is traveling downward.