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JEE Main202117 Mar 2021Morning ShiftPhysicsRotational MotionActual

A triangular plate is shown. A force F → = 4 i ^ - 3 j ^ is applied at point P . The torque at point P with respect to point O and Q are:

Options

  1. A- 15 - 20 3 , 15 - 20 3
  2. B15 + 20 3 , 15 - 20 3
  3. C15 - 20 3 , 15 + 20 3
  4. D- 15 + 20 3 , 15 + 20 3

Correct answer

A. - 15 - 20 3 , 15 - 20 3

Step-by-step solution

F → = 4 i ^ - 3 j ^ r → 1 = 5 i ^ + 5 3 j ^ and r → 2 = - 5 i ^ + 5 3 j ^ Torque about ' O ' τ → O = r → 1 × F → = - 15 - 20 3 k ^ Torque about ' Q ' τ → Q = r → 2 × F → = 15 - 20 3 k ^

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