A point of application of a force F→=5i^−3j^+2k^  is moved from r→1=2i^+7j^+4k^  top r→2=−5i^+2j^+3k^  The work done is:

Displacement of the point is r→2−r→1=(−5i^+2j^+3k^)−(2i^+7j^+4k^) =−7i^−5j^−k^ Work done W=F→.(r→2−r→1) =(5i^−3j^+2k^).(−7i^−5j^−k^) =−35+15−2 =−22unit