The position of a particle is given by `vecr = hati + 2hatj - hatk` and its linear momentum is given by `vecp = 3hati+4 hatj - 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

`vecL = vecr xx vecp = |{:(hati , hatj , hatk) , (1, 2, -1) , (3 , 4 , -2):}|`
`= hati (-4 + 4 ) - hatj (-2 + 3) + hatk (4 - 6) = 0 hati 0 1 hatj - 2hatk`
`vecL` has components along-yaxis and -z axis but it has no component in the x-axis . The angular momentum is in yz plane i.e., perpendicular to x-axis .