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Question 1:

Which of the following statements describes the conservation of angular momentum?

A) Angular momentum is always conserved in all systems
B) Angular momentum is conserved only in the absence of external torques
C) Angular momentum is conserved only in the absence of external forces
D) Angular momentum is never conserved

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Explanation: The correct answer is B) Angular momentum is conserved only in the absence of external torques. Angular momentum is conserved when the net external torque acting on a system is zero, meaning there are no external torques causing changes in the system's rotational motion.

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Question 2:

Which of the following situations represents the conservation of angular momentum?

A) A spinning ice skater pulling their arms inward, causing an increase in their rotational speed
B) A rotating wheel experiencing an external torque, resulting in a change in its angular momentum
C) A spinning top slowing down due to frictional forces acting on it
D) None of the above

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Explanation: The correct answer is D) None of the above. Conservation of angular momentum occurs when there are no external torques acting on a system. In option A, the ice skater's change in rotational speed indicates a change in angular momentum due to an external torque. Option B also involves an external torque. Option C involves a change in angular momentum due to external forces (friction). In all these cases, angular momentum is not conserved.

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Question 3:

Which of the following situations illustrates the conservation of angular momentum?

A) A spinning top maintaining a constant angular velocity
B) A rotating bicycle wheel slowing down gradually due to air resistance
C) A spinning gyroscope experiencing a change in its angular momentum
D) None of the above

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Explanation: The correct answer is A) A spinning top maintaining a constant angular velocity. When a spinning top maintains a constant angular velocity, it indicates the conservation of angular momentum. There are no external torques acting on the top to change its angular momentum.

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Question 4:

Which of the following situations violates the conservation of angular momentum?

A) A figure skater performing a spinning jump and then extending their arms outward
B) A rotating bicycle wheel experiencing an external torque causing it to speed up
C) A rotating planet gradually slowing down its rotation due to tidal forces
D) None of the above

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Explanation: The correct answer is A) A figure skater performing a spinning jump and then extending their arms outward. When a figure skater extends their arms outward during a spinning jump, their moment of inertia increases, causing a decrease in angular velocity. This violates the conservation of angular momentum, as there is no external torque involved. In options B and C, external torques are present, so the conservation of angular momentum is not violated.

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Question 5:

Which of the following quantities remains constant when the moment of inertia changes in a system?

A) Angular velocity
B) Angular momentum
C) Torque
D) Rotational kinetic energy

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Explanation: The correct answer is B) Angular momentum. When the moment of inertia changes in a system, the angular momentum remains constant if there are no external torques acting on the system. The conservation of angular momentum states that in the absence of external torques, the total angular momentum of a system remains constant.