A uniform disc rolls without slipping such that the velocity of its centre of mass is 6v0 and its angular velocity is 2v0/R, where R is the radius of the disc. The distance of the instantaneous axis of rotation (IAR) from the centre of mass is

Correct answer: 3R

Solution

For any rigid body in plane motion, the speed of the centre of mass equals omega times the distance from the IAR. So d = v_cm / omega = 6v0 / (2v0/R) = 3R.

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