The torque of the force `vecF=(2hati-3hatj+4hatk)N` acting at the point `vecr=(3hati+2hatj+3hatk)m` about the origin be

Options

A. `6hati - 6 hatj +12 hatk`
B. `17hati - 6 hatj -13 hatk`
C. `-6hati + 6 hatj -12 hatk`
D. `-17hati + 6 hatj -13 hatk`

Answer

B

Explanation

`vectau = vecr xx vecF`
`=|{:(hati,hatj,hatk),(3,2,3),(2,-3,4):}|`
`= hati ( 8+ 9) - hatj (12 - 6) + hatk(-9-4)`
`= 17 hati - 6 hatj - 13 hatk`