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AP EAMCET202124 Aug 2021Morning ShiftPhysicsRotational MotionActual

A thin rod of mass m and length 2 l is made to rotate about an axis passing through its centre and perpendicular to it. Its angular velocity changes from 0 to in time t . What is the torque acting on the rod?

Options

  1. Am l^2 12 t
  2. Bm l^2 t
  3. Cm l^2 3 t
  4. D4 m l^2 3 t

Correct answer

C. m l^2 3 t

Step-by-step solution

Given that, mass of rod =m Length of rod , L=2 l Initial and final angular velocities are 0 and respectively, Time taken =t We know that, torque acting on body having moment of inertia ( (I) and angular acceleration ( ) is where, =I aligned I & = 1 12 M L^2= 1 12 m(2 l)^2 & = 1 3 m l^2 aligned and = _f- _i t = -0 t = t Now, substituting the values, we get = 1 3 m l^2 t

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