The work, W, done by a constant force, F, which acts on a
body during a displacement, d, is given by
W
= F·d = F*d*cos(q)
where q is the angle between F and
d.
This implies that there must be a component of the force in the direction
of the displacement for work to be done.
Note that work is a scalar, F and d are vectors with
magnitudes F and d.