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
- AL A > L B
- BL A = L B
- CThe relationship between L A and L B depends upon the slope of the line A B
- 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 .