Question

A particle of mass m is moving yz- plane with
a uniform velocity v with its trajectory running
parallel to +ve y-axis and intersecting z-axis
at z=a. The change in its angular momentum
about the origin as it bounces elastically from
a wall at y = constant is
1) mva i
2) 2 mva i
3)-mva i
4) -2amv i

Answer 1

Answer:

mvaeˆx

2mvaeˆx

ymveˆx

2ymveˆx

Answer :

B

Solution :

The initial velocity is vi=veˆy and after reflection from the wall, the final velocity is vf=−veˆy. The trajectory is described as position vector r×yeˆy+aeˆz

Hence, the change in angular momentum is

τ×m(vf−vi)=2mvaeˆx

Explanation: