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AP EAMCET202021 Sep 2020Evening ShiftPhysicsCenter of Mass, Momentum and CollisionActual

A uniform circular disc has radius (r ). A square portion of diagonal (r ) is cut from it. The centre of mass of the remaining disc from the centre of disc is

Options

  1. A( r 2-4 )
  2. B( r 3-3 )
  3. C( r 2-5 )
  4. D( 2 r 1-2 )

Correct answer

A. ( r 2-4 )

Step-by-step solution

Suppose, the mass of circular disc is (M ). A square portion of diagonal (r ) is cut from it. Assuming centre of mass of circle to be origin. Centre of mass of square portion will be at distance ( r 2 ) from it. ( ) Side of square (= r 2 ) Area of square (= ( r 2 )^2= r^2 2 ) Mass of square, (m=M r^2 / 2 r^2 ) (m= M 2 ) Centre of a mass of remaining disc from the centre of disc, ( aligned x & =M 0- m r / 2 M-m = - M 2 r 2 M- M 2 = -r 4 -2 x & = r 2-4 aligned )

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