Angular Momentum (Not the usual Turntable Question)

AI Thread Summary
The discussion revolves around a physics problem involving a dog walking on a stationary turntable and the conservation of angular momentum. The initial and final angular momentum of the system is stated to be zero, as the turntable rotates in the opposite direction to the dog's movement. Participants express uncertainty about how to proceed with the calculations after establishing this conservation principle. A hint is provided to consider the torque acting at the center of the turntable due to the dog's movement. The conversation emphasizes the importance of analyzing forces and torques rather than focusing solely on final velocities.
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Homework Statement



A dog of mass m is standing on the edge of a stationary horizontal turntable of totational inertia I and radius R. The dog walks once around the circumference of the turntable.

What fraction of a full circle does the dog's motion make with respect to the ground? Express your answer in terms of m, I and R. Ignore friction at the axle of the turntable.

Homework Equations



Conservation of angular momentum

The Attempt at a Solution



The turntable will rotate in the opposite direction as motion of the dog. Hence initial angular momentum = final angular momentum = zero.

Final angular momentum = Angular momentum of the dog wrt the ground - angular momentum of the table wrt the ground = 0

Is it correct so far?

I'm not sure as to how to proceed after that. Can anyone help me on this? Thanks!
 
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I don't think that will lead you to the right answer. We don't need to find any final velocities (so I think no use of applying COAM).
I will give you a hint.
Consider the torque acting about the point of hinge (centre of the table) by the force-pair which causes the dog to move forward.
 

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