How did the concept of work come into existence? Well this is really a silly question. However I am curious to know about this topic.
Concept of each of the quantities discussed in physics have come into existence based on some basic human thoughts. For example if we are talking about force, it might have been termed based on the pull and push concept and then people discussed about it rigorously. Again displacement might have been termed based on our change in position.(I don't know for sure if these were the ways how their concept emerged, presented these just as examples)
Now how did the concept of work emerge? Why did the one who first thought about it formulated work as the dot product of force and the displacement caused by the force?
If we are at the initial stage of learning and understanding the nature we might have thought that standing for a long period of time has drained something from our body. Someone might have termed that imaginary thing as "energy". Again some have termed this as "work". So if we start to think from that scenario we might consider standing for a long period is work. So what did it cause the enthusiast to exclude these type of cases where dot product of force and displacement yields zero while defining "work"?
I am apologising for asking such a wierd and a baseless question. I could not get rid of this question from my mind so thought of asking it here.
 A: The unit of work and energy is the Joule, named after James Joule who did early work on this type of thing.
https://en.wikipedia.org/wiki/James_Prescott_Joule
Joule set up paddle wheels in a tub of water and by allowing dropping weights to turn them (via a rope system) he carefully measured how much heat energy was generated.  Joule would have noticed that stationary weights gave no heating effect, but when the weights moved through a distance, the heating effect was produced, twice the distance, twice the heating effect etc...

Joule's apparatus for measuring the mechanical equivalent of heat.
In this way he found that the energy generated was equal to the force times the distance.
A: My guess is that the notion of work comes from using levers, pulleys, gears, all types of tools where there is a trade off between force and displacement.
If the job is to lift a weight between 2 levels, there are several ways to perform the task. Basically if the force is reduced the displacement is increased. Work is what is constant in the job: the product of force by displacement.
