Find the moment of ` vec F` about point (2, -1, 3), where force ` vec F=3 hat i+2 hat j-4 hat k` is acting on point (1, -1, 2).

Explanation

`vecF = 3hati + 2hatj - 4hatk`
A is (1,-1,2) P is ( 2, -1,3)
` vecPA= P.V. of A - P.V. of P`
`= (hati - hatj + 2hatk) - (2hati - hati - jatj + 3hatk)`
`= - hati - hatk`
Required vector moment = `vecPA xx vecF`
`(-hati-hatk) xx ( 3 hati + 2hatj - 4hatk)`
`=|{:(hati,hatj,hatk),(-1, 0 , -1) ,( 3,2,-4):}|`
`2hati- 7hatj - 2hatk`