Q.
A mass m is moving with a constant velocity along a line parallel to the x-axis, away from the origin. Its angular moment with respect to the origin
Angular momentum of the particle about origin O will be given by L→=r→×p→=m(r→×V→) or∣∣L→∣∣=L=mrV sinθ =mV(r sinθ)=mVh
Now, m,V and h all are constant
Therefore, angular momentum of particle about origin will remain constant. The direction of r→×v→ also remains the same (negative z direction)