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JEE Main202311 Apr 2023Morning ShiftPhysicsLaws of MotionActual

A coin placed on a rotating table just slips when it is placed at a distance of 1 cm from the centre. If the angular velocity of the table is halved, it will just slip when placed at a distance of _____ from the centre:

Options

  1. A8   cm
  2. B4     cm
  3. C1   cm
  4. D2   cm

Correct answer

B. 4     cm

Step-by-step solution

The coin will slip when μ m g = m ω 2 r ⇒ μ g = ω 2 × 1   cm       . . . ( i ) Now, ω ' = ω 2 μ g = ω 2 2 R       . . . ( i i ) Hence we can write from (i) and (ii) ω 2 × 1   cm = ω 2 4 R ⇒ R = 4   cm

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