Question

When there is an angle between the force and the displacement, W = F·d cos θ. Is this true or false?

Answer 1

Take into account that the work done by the force F can be written as follow:

$\vec{W}=\vec{F}\cdot\vec{d}$

Consider that for a dot product between vectors you have:

$\vec{F}\cdot\vec{d}=Fd\cos \theta$

where θ is the angle in between the vectors F and d.

Then, related to the given statemen, it is true that angle θ is the angle between force and displacement.