A disc of radius 2 m and mass 100 k g rolls on a horizontal floor. Its centre of mass has speed of 20 c m s - 1 . How much work is needed to stop it?

Question

A disc of radius 2 m and mass 100 k g rolls on a horizontal floor. Its centre of mass has speed of 20 c m s - 1 . How much work is needed to stop it?, 3 J, 30 k J, 2 J, 1 J

MARKS App · Accepted Answer

Energy of the cylinder = 1 2 m v 2 + 1 2 I ω 2 = 1 2 m v 2 + 1 2 m r 2 2 v 2 r 2 = 3 4 m v 2 = 3 4 × 100 × 20 × 10 - 2 2 = 3 J

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