question_answer

A particle of mass m moves along line PC with velocity v as shown. What is the angular momentum of the particle about O? [AIEEE 2002]

A)   mvL              

B)   mvl

C)   mvr                

D)        0

Correct Answer: B

Solution :

[b] The angular momentum of a body of constant mass and constant velocity depends upon the perpendicular distance from a fixed point (origin).

Angular momentum of particle about 0

\[L=m(r\times v)\]

\[\left| L \right|=mv\sin \theta =mv(r\sin \theta )=mvl\]