Question

A particle acted on by constant forces `4veci+vecj-3veck and 3veci+vecj-veck` is displaced from the point `veci+2vecj+3veck` to the point `5veci+4vecj+veck.` Find the total work done by the forces

Answer 1

`Here vecF=vecF_(1)+vecF_(2)=(4hati+hatj-3hatk)+(3hati+hatj-hatk)=7hati+2hatj-4hatk`
`and vecd=vecd_(2)-vecd_(1)(5hati+4hatj+hatk)-(hati+2hatj+3hatk)=4hati+2hatj-2hatk`
Work done = `vecF.vecd`
`=(7hati+2hatj-4hatk).(4hati+2hatj-2hatk)`
= (7) (4) + (2) (2) + (-4) (-2)
= 28 + 4 +8 = 40 units.