Question

Find the work done in moving an object along a vector r=3i+2j-5k, if the applied force is F=2i-j-k

Answer 1

The work is equivalent to the dot product of the two vectors:

$W=rF=(3i+2j-5k)(2i-j-k)=\\=3*2+2*(-1)+(-5)*(-1)=9.$