# When the angular momentum of a rotating body is conserved, what can be inferred from it?

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When the angular momentum of a rotating body is conserved, what can be inferred from it?
1. Torque on the body is constant.
2. Torque on the body has become very high
3. Torque on the body is zero.
4. Nothing can be said about the torque.

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Correct Answer - Option 3 : Torque on the body is zero.

CONCEPT:

• Torque: The measure of the force that causes an object to rotate about an axis is known as torque.
• Angular momentum: The product of the Moment of Inertia of the body and angular velocity is known as angular momentum.
• Conservation of angular momentum: When there is no net torque on the body, its angular momentum is conserved.

EXPLANATION:

• Angular momentum Conservation: When in a system, there is no external torque then the total angular momentum (L) of the system will be conserved.
• So when in a system angular momentum is constant, it means net external torque on the body will be zero.
• Hence the correct answer is option 3.