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NTA Abhyas JEE Main2020PhysicsRotational MotionPractice

A particle of mass m moves in the X Y plane with a velocity v along the straight line A B . If the angular momentum of the particle with respect to origin O is L A when it is at A and L B when it is at B , then

Options

  1. AL A > L B
  2. BL A = L B
  3. CThe relationship between L A and L B depends upon the slope of the line A B
  4. DL A < L B

Correct answer

B. L A = L B

Step-by-step solution

From the definition of angular momentum, L = r × p = r m v sin ⁡ ∅ ( - k ^ ) Therefore, the magnitude of L is L = m v r sin ⁡ ∅ = m v d where d = r sin ⁡ ∅ is the distance of closest approach of the particle to the origin. As d is same for both the particles, hence L A = L B .

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