Concept of work in physical meaning

Generally, we mean work is muscular power, but in physics the term 'work' has different meaning.
i.e., when a constant force is applied on the object, then it moves some distance, then it has work to be done. Suppose the force is F and the distance moved is S, then the work done by the object is
W=F.S
This formula is applicable when force is applied in the direction its moved. But sometimes the force is applied making some angle 'O' with the direction of moving of the object. At the time, we take
force component along the direction of object moved i.e., FCosO
Then the work done by the object is W=(FCosO).S
For example, when a road roller moves along the horizontal direction, the force is applied in a direction of pulling that makes some angle with horizontal direction that roller moved.
Here is one point to remember is when O=90 degrees, then the work done by the object W=0.
This is the fact in case of electron moves around the nucleus, i.e., the centripetal force is along the radius vector towards the centre of circle, the motion of the body is along the direction of the tangent of circle, between these two the angle is 90 degrees.
It is surprised that when a man is holding a suitcase in air, according to physiological sense, he works hard, but according to physics, he is not yet doing any work because the force which applied on the suitcase causes no displacement.