If the particle of mass `m` is moving with constant velocity `v` parallel to x-axis in x-y plane as shown in (figure), Find its angular momentum with respect of origin at any time `t`.

Explanation

We know that angular momentum,
`vec(L)=vec(r )xxvec(p)` in terms of component becomes
`vec(L)=|(hat(i), hat(j), hat(k)) ,(x,y,z), (p_(x),p_(y) ,p_(z))|`
As motion is in x-y plane `(z=0 and P_(z)=0)`.
So `vec(L)=vec(k)(xp_(y)-yp_(x))`
Here `x=vt,y=b,p_(x)=mv`, and `p_(y)=0`
`:. vec(L)=vec(k)[vtxx0-b mv]=mvb hat(k)`