Question

`vecF = a hat i + 3hat j+ 6 hat k` and `vec r = 2hat i-6hat j -12 hat k`. The value of `a` for which the angular momentum is conserved is
A. `-1`
B. `0`
C. `1`
D. `2`

Answer 1

Correct Answer - A
`vec(tau)=vec(r)xxvec(F)` and `tau=(dL)/(dt)=0`