Question

explain briefly why work is not a vector quantity If force and displacement of both or vector quantities​

Answer 1

Because only that force contributes to work which is along the displacement (recall the definition of work done).

If force makes some angle with displacement only the cos component of that displacement contributes to work

force--->F

displacement---->x

As i said

x F cos theta= work done

so F.x=work(dot product means a scalar quantity)

Hope u got it.