The position of a particle is given by `r=hati+2hatj-hatk` and its linear momentum is given by `p=3hati+4hatj-2hatk`. Then its angular momentum, about the origin is perpendicular to

Options

A. yz-plane
B. z-axis
C. y-axis
D. x-axis

Answer

D

Explanation

`L=rxxP=|(hati,hatj,hatk),(1,2,-1),(3,4,-2)|`
`L=hati(-4+4)-hatj(-2+3)+hatk(4-6)`
`=-hatj-2hatk`
L has components along `-y` axi and `-z` axis. The angular momentum is in `y-z` plane, i.e., perpendicular to x-axis.