Find the torque due to force `vec(F)=2g=hat(i) -3hat(j)+4hat(k)` newton acting a point with position vector `vec(r )=3hat(i) + 2hat(j) + 3hat(k)` metre about the origin :

Options

A. `17hat(i) + 6hat(j) -13hat(k)`
B. `17hat(i) - 6hat(j) -13hat(k)`
C. zero
D. None of these

Answer

B

Explanation

`vec(tau)=vec(r)xxvec(F)=(3hati + 2hatj + 3hatk) xx (2hati - 3hatj +4hatk)`
`vec(tau)=`
`hati(8-)(-9)+hatj(6-12)+hatk (-9-4)`
`17hati - 6hatj -13hatk`