A circular platform is mounted on a frictionless vertical axle. Its radius R=2 m and its moment of inertia about the axle is 200 kg m^2. It is initially at rest. A 50 kg man stands on the edge of the platform and begins to walk along the edge at the speed of 1 m s^(-1) relative to the ground. Time taken by the man to complete one revolution with respect to disc is

A circular platform is mounted on a frictionless vertical axle. Its ra

1.	A circular platform is mounted on a frictionless vertical axle. Its radius R=2 m and its moment of inertia about the axle is 200 kg m^2. It is initially at rest. A 50 kg man stands on the edge of the platform and begins to walk along the edge at the speed of 1 m s^(-1) relative to the ground. Time taken by the man to complete one revolution with respect to disc is
Answer» `pi s` `(3pi)/2 s` `2pi s` `pi/2 s` SOLUTION :USING angular momentum conservation, `L_i=0 , L_f= MVR-I omega`, so , `mvR = I omega` `omega=(mvR)/I=(50xx1xx2)/200=1/2` For ONE complete revolution, `(v+omegaR)t=2piR` `(1+1/2xx2)t=2pixx2 rArr t=2pi s`.

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