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JEE Main202125 Jul 2021Evening ShiftPhysicsRotational MotionActual

A solid disc of radius 20 cm and mass 10 kg is rotating with an angular velocity of 600 rpm , about an axis normal to its circular plane and passing through its centre of mass. The retarding torque required to bring the disc at rest in 10 s is _________ π × 10 - 1 N m

Correct answer

0

Step-by-step solution

τ = Δ L Δ t = I ω f - ω i Δ t τ = m R 2 2 × [ 0 - ω ] Δ t = 10 × 20 × 10 - 2 2 2 × 600 × π 30 × 10 = 0 . 4 π = 4 π × 10 - 1

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