A particle of mass `m` is moving along the line `y=b,z=0` with constnat speed `v`. State whether the angular momentum of particle about origin is increasing. Decreasing or constant.

Explanation

`vec(|L|)= mvr sin theta`
`= mvr_(bot)`
= mvb
`:. vec(|L|)` = constant asm, v and b all are constants.
Direction of `vec(r) xx vec(v)` also remains the same.
Therefore, angular momentum of particle about origin remains constant with due course of time.