Conservation of angular momentum
Describe the behavior of a system using conservation of angular momentum.
The total angular momentum of a system about a rotational axis is the sum of the angular momenta of the system’s constituent parts about that rotational axis.
Any change to a system’s angular momentum must be due to an interaction between the system and its surroundings.
The angular impulse exerted by one object or system on a second object or system is equal and opposite to the angular impulse exerted by the second object or system on the first. This is a direct result of Newton’s third law.
A system may be selected so that the total angular momentum of that system is constant.
The angular speed of a nonrigid system may change without the angular momentum of the system changing if the system changes shape by moving mass closer to or farther from the rotational axis.
If the total angular momentum of a system changes, that change will be equivalent to the angular impulse exerted on the system
Describe how the selection of a system determines whether the angular momentum of that system changes.
Angular momentum is conserved in all interactions.
If the net external torque exerted on a selected object or rigid system is zero, the total angular momentum of that system is constant.
If the net external torque exerted on a selected object or rigid system is non zero, angular momentum is transferred between the system and the environment.
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