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NTA Abhyas JEE Main2020PhysicsRotational MotionPractice

A merry-go-round is at rest, pivoted on a frictionless axis. A child of mass m runs along the path tangential to the rim with speed v and jumps on to merry-go-round. If R is the radius of the merry-go-round and I is the moment of inertia, then the angular velocity of the merry-go-round and the child is

Options

  1. Am v R m R 2 + I
  2. Bm v R I
  3. Cm R 2 + I m v R
  4. DI m v R

Correct answer

A. m v R m R 2 + I

Step-by-step solution

By law of conservation of angular momentum mvR = I system ω ⇒ mvR = I + mR 2 ω ⇒ ω = mvR I + mR 2

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