Pregunta 1
Pregunta
An object that's moving with constant speed travels once around a circular path. Which of the following is/are true concerning this motion?
I. The displacement is zero.
II. The average speed is zero.
III. The acceleration is zero.
Respuesta
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I only
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I and II only
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I and III only
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III only
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II and III only
Pregunta 2
Pregunta
At time t = t_1, an object's velocity is given by the vector v_1 shown below. A short time later, at t = t_2, the object's velocity is the vector v_2. If the magnitudes of v_2 and v_1 are equal, which of the following vectors best illustrates the object's average acceleration between t = t_1 and t = t_2?
Pregunta 3
Pregunta
A rock is thrown off a 30 m cliff at a 45° angle above the horizontal. When the rock is 15 m above the ground, what is its acceleration?
Respuesta
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0
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1/2 g, downward
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g, downward
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1/2 g, upward
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g, upward
Pregunta 4
Pregunta
A baseball is thrown straight upward. What is the ball's acceleration at its highest point?
Respuesta
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0
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1/2 g, downward
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g, downward
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1/2 g, upward
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g, upward
Pregunta 5
Pregunta
How long would it take a car, starting from rest and accelerating uniformly in a straight line at 5 m/s^2, to cover a distance of 200 m?
Respuesta
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9.0 s
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10.5 s
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12.0 s
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15.5 s
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20.0 s
Pregunta 6
Pregunta
A rock is dropped off a cliff and strikes the ground with an impact speed of 30 m/s. How high was the cliff?
Pregunta 7
Pregunta
A stone is thrown horizontally with an initial speed of 10 m/s from a bridge. If air resistance could be ignored, how long would it take the stone to strike the water 80 m below the bridge?
Pregunta 8
Pregunta
A soccer ball, at rest on the ground, is kicked with an initial velocity of 10 m/s at a launch angle of 30°. Calculate its total flight time, assuming that air resistance is negligible.
Pregunta 9
Pregunta
A stone is thrown horizontally with an initial speed of 30 m/s from a bridge. Find the stone's total speed when it enters the water 4 seconds later. (Ignore air resistance.)
Respuesta
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30 m/s
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40 m/s
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50 m/s
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60 m/s
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70 m/s
Pregunta 10
Pregunta
Which one of the following statements is true concerning the motion of an ideal projectile launched at an angle of 45° to the horizontal?
Respuesta
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The acceleration vector points opposite to the velocity vector on the way up and in the same direction as the velocity vector on the way down.
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The speed at the top of the trajectory is zero.
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The object's total speed remains constant during the entire flight.
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The horizontal speed decreases on the way up and increases on the way down.
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The vertical speed decreases on the way up and increases on the way down.
Pregunta 11
Pregunta
The position of an object moving in a straight line is given by the equation x = (3t^3+7t+5) m, where t is in seconds. What is the object's acceleration at time t = 5 seconds?
Respuesta
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415 m/s^2
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232 m/s^2
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115 m/s^2
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90 m/s^2
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35 m/s^2
Pregunta 12
Pregunta
The velocity of an object moving in a straight line is graphed above. If x = 3.0 m at t = 0 s, what is the position of the particle at t = 3.0 s?