Find the work done by the force `F=3 hat i- hat j-2 hat k` acrting on a particle such that the particle is displaced from point `A(-3,-4,1) to B(-1,-1,-2)dot`

Answer

9

Explanation

Here `vecF = 3hati -hatj - 2hatk`
`vecAB = P.V of B - P.V. of A `
`( -hati - hatj - 2hatk) - (3hati - 4hatj + hatk) ]`
` 2hati + 3hatj -3hatk`
Let `vecs = vecAB` be the displacement vector Now work done = `vecF .vecs`
`(3hati - hati - 2hatk) . (2hati + 3hatj - hatk)` ltbrge 6-3 + 6 =9