# Physics - Conservation of Angular Momentum

a man is standing on the center of a platform that is rotating without friction. his arms are outstretched holding a brick in each hand. the rotational inertia of the system consists of the man, bricks, and platform about the central vertical axis of the platform. by moving the bricks, the man decreases the rotational inertia of the system.

which quantities of angular momentum are conserved?

-the platform
-the bricks
-the system
-the man

i chose the platform. is there more than one answer to this question?

There is only one answer to the question. Only the total angular momentum of THE SYSTEM is conserved because external forces are not applied to it. The parts of the syatem CAN have their angular momenta go up or down, as a result of internal forces.

ook. i get it. thank you.

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