JEE Mains · Physics · STD 11 - 6. system of particles and rotational motion
A bob of mass \(m\) attached to an inextensible string of length \(l\) is suspended from a vertical support. The bob rotates in a horizontal circle with an angular speed \(\omega\ rad/s\) about the vertical. About the point of suspension:
- A angular momentum changes in magnitude but not in direction
- B angular momentum changes in direction but not in magnitude
- C angular momentum changes both in direction and magnitude
- D angular momentum is conserved
Answer & Solution
Correct Answer
(B) angular momentum changes in direction but not in magnitude
Step-by-step Solution
Detailed explanation
Torque working on the bob of mass \(m\) is, \(\tau = mg \times \ell \sin \theta .\,\). (Direction parallel to plane of rotation of particle) As \(\tau \) is perpendicular to \(\overrightarrow L \), direction of \(L\) changes but magnitude remains same.
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