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18 Cards in this Set
- Front
- Back
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A coach hits a ball with his bat. The ball nearly travels horizontal towards the short stop. Did the coach, via the bat, do any work on the ball as it was hit? |
Yes, work was done on the ball because during the time the force acted on the ball, the bat and ball moved through some distance. |
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Two balls of equal size are dropped from the same height from a roof. One ball has twice the mass of the other. When the balls reach the ground, how do the Kinetic energies of the two balls compare? |
The lighter one has one half as much Kinetic Energy as the other does. |
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After an ice storm, ice falls from one of the top floors of a 65 story building. Falling freely due to gravity... What happens? |
The Kinetic Energy of the ice increases by equal amounts for equal distances. |
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Two identical balls are thrown from the room. One ball is thrown upward with an initial speed. The second ball is thrown downward with the same initial speed. When the ball reaches the ground, how does the Kinetic Energy compare with the balls? |
The Kinetic Energy of the balls will be the same. |
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A rubber ball is dropped from a height. The ball hits the floor and reaches a height of 2h/3. How can you use the principal of conservation of mechanical energy to interpret this observation? |
Work was done on the ball by non-conservative forces that resulted in the ball having less total mechanical energy after the bounce. |
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A climber pulls supply up a mountain at a constant speed. What is not done? |
The work done on the pack by gravity is zero joules. |
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Equal balls of size are dropped from the same height of a roof. One ball is twice the mass than the other. When the balls reach the ground, how do the KE of the two compare? |
The lighter one has one half as much KE as the other does. |
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An astronaut droos a golf ball that is initially at rest from a cliff off the surface of the moon. The ball falls freely under the influence of gravity. What is true as the ball falls? |
The ball will gain an equal amount of momentum during each second. |
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A person jumos from the roof of a tall building, but no injury occurs after landing on a airfilled pad. Why no injury? |
The bag increased the amount of time during which momentum is changing and reduces the average force on the person. |
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A small astroid collides with a planet. What happens during the collision? |
The astroid exerts the same amount of force on the planet as the planet exerts on the astroid. |
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Object A is traveling North while object B is traveling due South along the same line. They have a head on collision. What best describes the velocities of the objects after the collision? |
The final velocities of A and B could be equal to zero m/s. |
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A water balloon is dropped from a 3rd story building. It bursts when it hits the ground. How much KE is transferred to the result of the collision? |
Zero Joules |
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Ball thrown downward and its speed is v just before hitting the ground. After the collision with the earth it heads upwards with a speed v. What's happening? |
Only the momentum of the ball is changed by the collision. |
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Two identical cars colide on an icy intersection. Car A was stopped at a red light. Car B was moving at a speed v when it suffered a perfectly inelastic collision with the back end of car A. With what speed did the two cars slide into the intersection? |
V/2 |
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A girl is swinging at the park. As she goes back and forth, she follows a oath that is part of a vertical circle. Speed is max at lowest point and temp 0m/s what's happening? |
The force which is radially outward from the center of the circle and the tension in the chains of the swing, which is directed upward. |
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You are riding in the forward passenger seat of a car as it travels straight. The car is constant speed as it follows a sharp unbanjed curve. You feel the door pushing on the right side of your body. What horizontal force acts on you? |
A static frictional force between you and the seat, and a force pushing you toward the door. |
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The max speed at which a car can safely negotiate an unbanjed curve depends on all of the following factors besides... |
The coefficient of Kinetic friction between the road and the tires. |
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A ball is attached at the end of a string. It's whirled in a horizontal circle of radius R at a constant speed v. How can the centripital acceleration of the ball be increased by a factor of two? |
Keep the speed fixed and decrease the radius by a factor of two. |
