Physics · Basic concepts of rotational motion, moment of a force, torque, angular momentum, conservation of angular momentum and its applications
A uniform rod is resting freely over a smooth horizontal plane. A particle movin
A uniform rod is resting freely over a smooth horizontal plane. A particle moving horizontally strikes at one end of the rod normally and gets stuck. Then This question has multiple correct options
- A. the momentum of the particle is shared between the particle and the rod and remains conserved
- B. the angular momentum about the mid-point of the rod before and after the collision is equal
- C. the angular momentum about the centre of mass of the combination before and after the collision is equal
- D. the centre of mass of the rod particle system starts to move translationally with the original momentum of the particle
Step-by-step solution
During the collision, no external horizontal forces act on the rod-particle system, so linear momentum is conserved. The initial momentum of the particle equals the total momentum of the system after collision, so the centre of mass moves with that momentum. Options A and C are also correct, but D directly follows from linear momentum conservation. Option B is false because the midpoint of the rod is not a fixed point, and angular momentum about a moving point is not generally conserved.
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