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Two horizontal discs of different radii ...

Two horizontal discs of different radii are free to rotate about their central vertical axes: One is given some angular velocity, the other is stationary. Their rims arc now brought in contact. There is friction between the rims. Then

A

the force of friction between the rims will disappear when the discs rotate with equal angular speeds.

B

the force of friction between the rims will disappear when the points of contact have equal linear velocities.

C

the angular momentum of the system will be conserved.

D

the rotational kinetic energy of the system will not be conserved.

Text Solution

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The correct Answer is:
B, D
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