Question

Find the torque of a force `(5 hati - 2 hatj + 7 hatk)` about the origin, which acts on a particle whose position vector is `(2 hati - hatj + hatk)`.

Answer 1

Here, `overset rarr(tau) = ? , overset rarr(F) = (5 hati - 2hatj + 7 hatk), overset rarr(r) = (2 hati - hatj + hatk)`
`overset rarr(tau) = overset rarr(r) xx overset rarr(F) = |[hati,hatj,hatk],[2,-1,1],[5,-2,7]|`
`overset rarr(tau) = hati (-7 + 2) -hati(14 -5)+hatk (-4+5) or overset rarr(tau) =- 5 hati - 9hatj + hatk`