Question

a particle suffers a displacement from r1 (1,2,3) to r2 (4,5,6) due to application of a force of magnitude F=20N.the forces acts along a vector A=4j+3k.if the quantity is defined as W=F delta R,find W.

Answer 1

r2-r1=3i+j-k
F=20(4j+3k)/√16+9
=20(4j+3k)/5
=16j+12k
W=F.(r2-r1)
=(16j+12k)(3i+j-k)
=0+16-12
W=4 units
Hope it helps u;)