Question 1
Question
An object of mass 2 kg has a linear momentum of magnitude 6 kg·m/s. What is this object's kinetic energy?
Question 2
Question
The graph shows the force on an object over time. If the object has a mass of 8 kg and is moving in a straight line, what is its change in speed?
Answer
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16 m/s
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14 m/s
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12 m/s
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10 m/s
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8 m/s
Question 3
Question
A box with a mass of 2 kg accelerates in a straight line from 4 m/s to 8 m/s due to the application of a force whose duration is 0.5 s. Find the average strength of this force.
Question 4
Question
A ball of mass m traveling horizontally with velocity v strikes a massive vertical wall and rebounds back along its original direction with no change in speed. What is the magnitude of the impulse delivered by the wall to the ball?
Question 5
Question
Two objects, one of mass 3 kg and moving with a speed of 2 m/s and the other of mass 5 kg and speed 2 m/s, move toward each other and collide head-on. If the collision is perfectly inelastic, find the speed of the objects after the collision.
Answer
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0.25 m/s
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0.5 m/s
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0.75 m/s
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1 m/s
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2 m/s
Question 6
Question
A student is trying to balance a meter stick on its midpoint. Given that m_1 = 6 kg and m_2 = 2 kg, how far from the left edge should the student hag a third mass, m_3 = 10 kg, to balance the meter stick?
Answer
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40 cm
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50 cm
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60 cm
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70 cm
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80 cm
Question 7
Question
Two objects move toward each other, collide, ad separate. If there was no net external force acting on the objects, but some kinetic energy was lost, then
Answer
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the collision was elastic and total linear momentum was conserved
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the collision was elastic and total linear momentum was not conserved
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the collision was not elastic and total linear momentum was conserved
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the collision was not elastic and total linear momentum was not conserved
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None of these
Question 8
Question
Three thin, uniform rods each of length L are arranged in the shape of an inverted U, as shown in the figure. The two rods on the arms of the U each have mass m; the third rod has mass 2m. How far below the midpoint of the horizontal rod is the center of mass of this assembly?
Question 9
Question
A car of mass 1,000 kg collides head-on with a truck of mass 2,000 kg. Both vehicles are moving at a speed of 21 m/s, and the collision is perfectly inelastic. After the crash, the two vehicles skid to a halt. Assuming friction is the only force acting on the vehicles after the collision, how much work is done by friction after the crash?
Answer
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73,500 J
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-73,500 J
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147,000 J
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-147,000 J
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220,500 J
Question 10
Question
Which of the following best describes a perfectly inelastic collision free of external forces?
Answer
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Total linear momentum is never conserved.
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Total linear momentum is sometimes conserved.
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Kinetic energy is never conserved.
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Kinetic energy is sometimes conserved.
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Kinetic energy is always conserved.