Test 4 Chapter 8 Momentum – Flashcards
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What represents the impulse of the force in a graph of force versus time?
answer
The impulse is equal to the area under the curve.
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When a constant force acts on an object, what does the object's change in momentum depend upon?
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1.The change in momentum depends upon the time interval during which the force acts.
2. The change in momentum depends upon the change in the velocity of the object.
3.The change in momentum depends upon the mass of the object.
4.The change in momentum depends upon the magnitude of the force.
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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?
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The impulse is the same in both situations.
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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?
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The ball experiences the greater momentum of change.
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Which of the following statements are true?
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1.The total momentum of an isolated system is constant.
2.The vector sum of forces acting on a particle equals the rate of change of momentum of the particle with respect to time.
3.The total momentum of any number of particles is equal to the vector sum of the momenta of the individual particles.
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For an elastic collision, which of the following statements are true?
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Kinetic energy is conserved.
Momentum is conserved.
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For an INELASTIC collision, which of the following statements are true?
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Momentum is conserved.
Kinetic energy is lost.
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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?
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The speed of the freight car decreases.
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A red ball with a velocity of +3.0 m/s collides head-on with a yellow ball of equal mass moving with a velocity of −2.0 m/s. What is the velocity of the two balls after the elastic collision?
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The velocity of the red ball is −2.0 m/s; the velocity of the yellow ball is +3.0 m/s.
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When a person steps forward out of a small boat onto a dock, the boat recoils backward in the water. Why does this occur?
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The total momentum of the system is conserved.
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Which statement must be true for the momentum of a system to be conserved?
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The net external force on the system is zero.
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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?
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The right shoe.
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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?
answer
1. An object's momentum is equal to the product of its mass and its velocity.
2. Momentum is a vector quantity.
