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4 Cards in this Set
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Yes or no: If the average velocity of a car during a trip along a straight road is positive, is it possible for the instantaneous velocity at some time during the trip to be negative?
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Yes, Velocity is calculated as final position- initial position/ time. As long as your final position is farther than your initial position, the average velocity will be positive. It's totally possible to have a negative velocity during the trip and still have a positive average velocity as long as you end up farther along then where you started.
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If the velocity of some object is not zero, can its acceleration ever be zero?
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Yes, Accleraion is change in velocity. If your velocity is non zero then you are moving. If your acceleration is zero when your velocity is non zero it means that you are moving at a constant rate.
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Is it possible for an object to have a positive velocity at the same time as it has a negative acceleration?
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Yes, You could be traveling foward but accelerationg backwards.
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A ball is thrown straight up in the air and it returns to its initial position. During the time the ball is in the air, which of the following statements is true?
1.Both the average acceleration and the average velocity are zero 2. The average acceleration is zero but the average velocity is not zero 3. The average velocity is zero but the average acceleration is not zero 4. Neither the average velocity nor the average acceleration are zero |
The average velocity is zero but the average acceleration is not zero. Since the ball returns to its initial position, the displacement is zero so the average velocity has to be zero bacause v= xf-xi/ t, the acceleration is constant at -9.8m/s2, the force of gravity
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