A particle of mass `2 mg` located at the position `(hat i+ hat k) m` has a velocity `2(+ hat i- hat j + hat k) m//s`. Its angular momentum about `z-`axis in `kg-m^(2)//s` is :

Options

A. `+4`
B. `+8`
C. `-4`
D. `-8`

Answer

D

Explanation

About origin, angular momentum will be
`m(rxxv)=2|{:(hat(i),hat(j),hat(k)),(1,1,0),(2,-2,2):}|=4 hat(i)-4hat(j)-8hat(k)`
Therefore, component of angular momentum about Z-axism would be `-8 "kgm"^(2)s^(-1)`