Question 1

A 4.00 kg object is moving at 5.00 m/s NORTH. It strikes a 6.00 kg object that is moving EAST at 2.00 m/s. The objects undergo a perfectly inelastic (stick together)  collision. The velocity of the 6.00 kg object after the collision is

Accepted Answer

A)   2.33 m/s at an angle of 35.0 degrees NORTH of EAST.
B)   2.33 m/s at an angle of 59.0 degrees NORTH of EAST.
C)   2.00 m/s at an angle of 59.0 degrees NORTH of EAST.
D)   2.00 m/s at an angle of 45.0 degrees NORTH of EAST.
E)   2.33 m/s at an angle of 45.0 degrees NORTH of EAST.F) B) and C)
G) B) and E)

Question 2

A 30.00 kg mass falls from a height of 2.000 m. The magnitude of the momentum of the mass just before it hits the ground is

Accepted Answer

A)   144.2 kg m/s.
B)   187.8 kg m/s.
C)   320.0 kg m/s.
D)   442.4 kg m/s.
E)   502.1 kg m/s.F) D) and E)
G) C) and D)

Question 3

A 250 g sticky hockey puck slides along a frictionless, horizontal ice surface at 75 m/s in the +x direction. It collides with a 500 g sticky puck originally sliding at 25 m/s in the -y direction. They collide perfectly inelastically. How much kinetic energy is lost in this collision?

Accepted Answer

A)   521 J
B)   779 J
C)   520 J
D)   More information is neededE) A) and D)
F) B) and D)

Question 4

A machine gun fires 60.0 gram bullets at a rate of 6 bullets per second. If the speed of the bullets is 600 m/s, then the magnitude of the average recoil force on the machine gun is

Accepted Answer

A)   67.0 N.
B)   75.0 N.
C)   94.0 N.
D)   109 N.
E)   216 N.F) C) and D)
G) A) and B)

Question 5

A 100 kg mass, initially at rest, is blown apart into a 60 kg piece and a 40 kg piece. After the blast, the two masses are moving apart with a relative velocity of 60 m/s. The speed of the 60 kg mass is

Accepted Answer

A)   88 m/s.
B)   67 m/s.
C)   51 m/s.
D)   40 m/s.
E)   24 m/s.F) A) and E)
G) C) and E)

Question 6

A rocket of length 80 m sits on a launch pad in outer space. The center of mass of the combined rocket and launch pad system is located in the center of the launch pad. The rocket is launched and reaches a distance of 100,000 km from the starting position. Where is the location of the center of mass of the total rocket-fuel-launch pad system then?

Accepted Answer

A)   at the center of the launch pad
B)   at the starting position
C)   100,000 km from the launch pad
D)   80 m from the launch pad
E)   50,000 km from the launch padF) B) and E)
G) A) and D)

Question 7

A 100.0 kg mass is blown apart into a 95.00 kg piece and a 5.000 kg piece. After the blast, the two masses are moving apart with a relative velocity of 100.0 m/s. The kinetic energy of the 95.00 kg mass after the explosion is

Accepted Answer

A)   1,190 J.
B)   8,600 J.
C)   18,750 J.
D)   22,560 J.
E)   23,750 J.F) B) and E)
G) B) and D)

Question 8

A ball bearing rolls along a smooth horizontal tabletop and crashes head-on into a second, stationary ball bearing of half its mass. If both ball bearings roll in the x-direction only (either positive or negative)  and the initially stationary ball is observed to have a velocity of +2.4 m/s after the collision, what was the initial speed of the first ball bearing? Assume the collision is elastic.

Accepted Answer

A)   More information is required
B)   7.2 m/s
C)   3.6 m/s
D)   1.8 m/sE) B) and D)
F) A) and B)

Question 9

An astronaut in a space suit is motionless in outer space. The propulsion unit strapped to her back ejects some gas with a velocity of magnitude 40.0 m/s. The astronaut recoils with a velocity of 1.00 m/s in the opposite direction. If the mass of the astronaut and space suit after the gas is ejected is 100 kg and the mass of the gas ejected is 2.50 kg, then the total kinetic energy is

Accepted Answer

A)   2,050 J.
B)   3,430 J.
C)   4,150 J.
D)   5,070 J.
E)   6,320 J.F) A) and D)
G) D) and E)

Question 10

A 120 kg mass, initially at rest, is blown apart into an 80 kg piece and a 40 kg piece. After the blast, the two masses are moving apart with a relative velocity of 60 m/s. The total kinetic energy after the explosion is

Accepted Answer

A)   21 kJ.
B)   35 kJ.
C)   48 kJ.
D)   56 kJ.
E)   82 kJ.F) All of the above
G) A) and D)

Exam 7: Linear Momentum

Correct Answer
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A 100.0 kg mass is blown apart into a 95.00 kg piece and a 5.000 kg piece. After the blast, the two masses are moving apart with a relative velocity of 100.0 m/s. The kinetic energy of the 95.00 kg mass after the explosion is

Correct Answer
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A 120 kg mass, initially at rest, is blown apart into an 80 kg piece and a 40 kg piece. After the blast, the two masses are moving apart with a relative velocity of 60 m/s. The total kinetic energy after the explosion is

Correct Answer
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A machine gun fires 60.0 gram bullets at a rate of 6 bullets per second. If the speed of the bullets is 600 m/s, then the magnitude of the average recoil force on the machine gun is

Correct Answer
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Correct Answer
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A 30.00 kg mass falls from a height of 2.000 m. The magnitude of the momentum of the mass just before it hits the ground is

Correct Answer
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Correct Answer
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A 250 g sticky hockey puck slides along a frictionless, horizontal ice surface at 75 m/s in the +x direction. It collides with a 500 g sticky puck originally sliding at 25 m/s in the -y direction. They collide perfectly inelastically. How much kinetic energy is lost in this collision?

Correct Answer
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A 100 kg mass, initially at rest, is blown apart into a 60 kg piece and a 40 kg piece. After the blast, the two masses are moving apart with a relative velocity of 60 m/s. The speed of the 60 kg mass is

Correct Answer
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A 4.00 kg object is moving at 5.00 m/s NORTH. It strikes a 6.00 kg object that is moving EAST at 2.00 m/s. The objects undergo a perfectly inelastic (stick together) collision. The velocity of the 6.00 kg object after the collision is

Correct Answer
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Exam 7: Linear Momentum

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A 100.0 kg mass is blown apart into a 95.00 kg piece and a 5.000 kg piece. After the blast, the two masses are moving apart with a relative velocity of 100.0 m/s. The kinetic energy of the 95.00 kg mass after the explosion is

Correct AnswerverifiedShow Answer

A 120 kg mass, initially at rest, is blown apart into an 80 kg piece and a 40 kg piece. After the blast, the two masses are moving apart with a relative velocity of 60 m/s. The total kinetic energy after the explosion is

Correct AnswerverifiedShow Answer

A machine gun fires 60.0 gram bullets at a rate of 6 bullets per second. If the speed of the bullets is 600 m/s, then the magnitude of the average recoil force on the machine gun is

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A 30.00 kg mass falls from a height of 2.000 m. The magnitude of the momentum of the mass just before it hits the ground is

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A 250 g sticky hockey puck slides along a frictionless, horizontal ice surface at 75 m/s in the +x direction. It collides with a 500 g sticky puck originally sliding at 25 m/s in the -y direction. They collide perfectly inelastically. How much kinetic energy is lost in this collision?

Correct AnswerverifiedShow Answer

A 100 kg mass, initially at rest, is blown apart into a 60 kg piece and a 40 kg piece. After the blast, the two masses are moving apart with a relative velocity of 60 m/s. The speed of the 60 kg mass is

Correct AnswerverifiedShow Answer

A 4.00 kg object is moving at 5.00 m/s NORTH. It strikes a 6.00 kg object that is moving EAST at 2.00 m/s. The objects undergo a perfectly inelastic (stick together) collision. The velocity of the 6.00 kg object after the collision is

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