The velocity of the center of mass of a system of particles changes as v = 4.5 t + 2.4 t2 + 1.1 t3, where v is in meters per second. If the system starts from rest at t = 0, what is its acceleration at t = 3.0 s?

A) 7.1 m/s2 B) 14 m/s2 C) 20 m/s2 D) 49 m/s2 E) 65 m/s2 A) 7.1 m/s2 B) 14 m/s2 C) 20 m/s2 D) 49 m/s2 E) 65 m/s2

The velocity of the center of mass of a system of particles changes as v = 4.5 t + 2.4 t2 + 1.1 t3, where v is in meters per second. If the system starts from rest at t = 0, what is its position at t = 3.0 s?

A) 7.1 m B) 21 m C) 40 m D) 49 m E) 64 m A) 7.1 m B) 21 m C) 40 m D) 49 m E) 64 m

The force on a particle is given by F(t) = 0.71 t + 1.2 t2, in N. If the force acts from t = 0 to t = 2.0 s, the total impulse is:

A) 1.2 kg∙m/s B) 1.9 kg∙m/s C) 4.6 kg∙m/s D) 4.8 kg∙m/s E) 6.2 kg∙m/s A) 1.2 kg∙m/s B) 1.9 kg∙m/s C) 4.6 kg∙m/s D) 4.8 kg∙m/s E) 6.2 kg∙m/s

Exam 9: Center of Mass and Linear Momentum

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Two spacemen are floating together with zero speed in a gravity-free region of space. The mass of spaceman A is 120 kg and that of spaceman B is 90 kg. Spaceman A pushes B away from him with B attaining a final speed of 0.5 m/s. The final recoil speed of A is:

(Multiple Choice)

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Question 41

An elastic collision is one in which:

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Question 42

A 500-kg sack of coal is dropped on a 2000-kg railroad flatcar which was initially moving at 3 m/s as shown. After the sack rests on the flatcar, the speed of the flatcar is:

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Question 43

Block A, with a mass of 2.0 kg, moves along the x axis with a velocity of 5.0 m/s in the positive x direction. It suffers an elastic collision with block B, initially at rest, and the blocks leave the collision along the x axis. If B is much more massive than A, the velocity of A after the collision is:

(Multiple Choice)

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Question 44

A rifle of mass M is initially at rest but free to recoil. It fires a bullet of mass m and velocity v (relative to the ground). After firing, the velocity of the rifle (relative to the ground) is:

(Multiple Choice)

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Question 45

The law of conservation of momentum applies to a system of colliding objects only if:

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Question 46

A golf ball of mass m is hit by a golf club so that the ball leaves the tee with speed v. The club is in contact with the ball for time T. The average force on the club on the ball during the time T is:

(Multiple Choice)

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Question 47

Cart A, with a mass of 0.2 kg, travels on a horizontal air track at 3 m/s and hits cart B, which has a mass of 0.4 kg and is initially at rest. After the collision the center of mass of the two cart system has a speed in m/s of:

(Multiple Choice)

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Question 48

The direction of the impulse on a struck baseball

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Question 49

A student's life was saved in an automobile accident because an airbag expanded in front of his head. If the car had not been equipped with an airbag, the windshield would have stopped the motion of his head in a much shorter time. Compared to the windshield, the airbag:

(Multiple Choice)

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Question 50

The center of mass of a system of particles remains at the same place if:

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Question 51

A cart loaded with sand slides forward along a horizontal frictionless track. As the cart moves, sand trickles out at a constant rate through a hole in the back of the cart. The acceleration of the cart is:

(Multiple Choice)

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Question 52

When you step on the accelerator to increase the speed of your car, the force that accelerates the car is:

(Multiple Choice)

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Question 53

A 640-N hunter gets a rope around a 3200-N polar bear. They are stationary, 20 m apart, on frictionless level ice. When the hunter pulls the polar bear to him, the polar bear will move:

(Multiple Choice)

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Question 54

The center of mass of a uniform disk of radius R is located:

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Question 55

The velocity of the center of mass of a system of particles changes as v = 4.5 t + 2.4 t² + 1.1 t³, where v is in meters per second. If the system starts from rest at t = 0, what is its acceleration at t = 3.0 s?

(Multiple Choice)

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Question 56

The velocity of the center of mass of a system of particles changes as v = 4.5 t + 2.4 t² + 1.1 t³, where v is in meters per second. If the system starts from rest at t = 0, what is its position at t = 3.0 s?

(Multiple Choice)

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Question 57

A 5-kg object can move along the x axis. It is subjected to a force in the positive x direction; a graph of F as a function of time t is shown below. Over the time the force is applied the change in the velocity of the object is:

(Multiple Choice)

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Question 58

The force on a particle is given by F(t) = 0.71 t + 1.2 t², in N. If the force acts from t = 0 to t = 2.0 s, the total impulse is:

(Multiple Choice)

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Question 59

At the same instant that a 0.50-kg ball is dropped from 25 m above Earth, a second ball, with a mass of 0.25 kg, is thrown straight upward from Earth's surface with an initial speed of 15 m/s. They move along nearby lines and pass without colliding. At the end of 2.0 s the velocity of the center of mass of the two-ball system is:

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Question 60

Showing 41 - 60 of 99

Exam 9: Center of Mass and Linear Momentum

Two spacemen are floating together with zero speed in a gravity-free region of space. The mass of spaceman A is 120 kg and that of spaceman B is 90 kg. Spaceman A pushes B away from him with B attaining a final speed of 0.5 m/s. The final recoil speed of A is:

An elastic collision is one in which:

A 500-kg sack of coal is dropped on a 2000-kg railroad flatcar which was initially moving at 3 m/s as shown. After the sack rests on the flatcar, the speed of the flatcar is:

A rifle of mass M is initially at rest but free to recoil. It fires a bullet of mass m and velocity v (relative to the ground). After firing, the velocity of the rifle (relative to the ground) is:

The law of conservation of momentum applies to a system of colliding objects only if:

A golf ball of mass m is hit by a golf club so that the ball leaves the tee with speed v. The club is in contact with the ball for time T. The average force on the club on the ball during the time T is:

Cart A, with a mass of 0.2 kg, travels on a horizontal air track at 3 m/s and hits cart B, which has a mass of 0.4 kg and is initially at rest. After the collision the center of mass of the two cart system has a speed in m/s of:

The direction of the impulse on a struck baseball

A student's life was saved in an automobile accident because an airbag expanded in front of his head. If the car had not been equipped with an airbag, the windshield would have stopped the motion of his head in a much shorter time. Compared to the windshield, the airbag:

The center of mass of a system of particles remains at the same place if:

A cart loaded with sand slides forward along a horizontal frictionless track. As the cart moves, sand trickles out at a constant rate through a hole in the back of the cart. The acceleration of the cart is:

When you step on the accelerator to increase the speed of your car, the force that accelerates the car is:

A 640-N hunter gets a rope around a 3200-N polar bear. They are stationary, 20 m apart, on frictionless level ice. When the hunter pulls the polar bear to him, the polar bear will move:

The center of mass of a uniform disk of radius R is located:

The velocity of the center of mass of a system of particles changes as v = 4.5 t + 2.4 t2 + 1.1 t3, where v is in meters per second. If the system starts from rest at t = 0, what is its acceleration at t = 3.0 s?

The velocity of the center of mass of a system of particles changes as v = 4.5 t + 2.4 t2 + 1.1 t3, where v is in meters per second. If the system starts from rest at t = 0, what is its position at t = 3.0 s?

A 5-kg object can move along the x axis. It is subjected to a force in the positive x direction; a graph of F as a function of time t is shown below. Over the time the force is applied the change in the velocity of the object is:

The force on a particle is given by F(t) = 0.71 t + 1.2 t2, in N. If the force acts from t = 0 to t = 2.0 s, the total impulse is:

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The velocity of the center of mass of a system of particles changes as v = 4.5 t + 2.4 t² + 1.1 t³, where v is in meters per second. If the system starts from rest at t = 0, what is its acceleration at t = 3.0 s?

The velocity of the center of mass of a system of particles changes as v = 4.5 t + 2.4 t² + 1.1 t³, where v is in meters per second. If the system starts from rest at t = 0, what is its position at t = 3.0 s?

The force on a particle is given by F(t) = 0.71 t + 1.2 t², in N. If the force acts from t = 0 to t = 2.0 s, the total impulse is: