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MHT CET 2021 (20 Sep, Shift 1) · Rotational Kinematics & Dynamics

Rotational Kinematics & Dynamics question from MHT CET 2021 (20 Sep, Shift 1)

Q40MHT CET 2021 · 20 SEP · SHIFT 1Easy

Rotational Kinematics & Dynamics

A disc of radius 0.4 m and mass one kg rotates about an axis passing through its centre and perpendicular to its plane. The angular acceleration of the disc is 10 rad/s $2$ . The tangential force applied to the rim of the disc is

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Answer: (c)

Disc: $I = \frac{1}{2}MR^2 = \frac{1}{2} \times 1 \times 0.16 = 0.08$ kg m $^2$
$\tau = I\alpha = 0.08 \times 10 = 0.8$ N m
$F = \frac{\tau}{R} = \frac{0.8}{0.4} = 2$ N
So the answer is (c) 2 N.

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