Work
Definition of Work
The work of physics and the work of the household word are considerably different concepts.
Let's assume that the object on a horizontal plane is horizontally pulled by means of a string.
Force to pull is F.
The object moved by F and only distance s moved.
In this case, it is expressed, "Force F worked for the object", and defines the amount as W=F¥s.
The difference between "Do Work" and "Be Worked" is confusing.
It is the following for the above-mentioned.
Force F does "Work" to the object.
As for the object, "Work" was done by force F.
Next, let's diagonally pull the object.
It is a case where force F acts diagonally.
In this case, you only have to think only about the element of the direction of s of force F.
A concrete definition is W=F¥s cosƒÆ.
F and s are the vector quantities.
Because W is a scalar product in the vector, it is the scalar quantities.
In a current example, it thought only about the movement of the direction of the straight line.
The work when moving along the curve only has to divide the route into a slight straight line, and to add up work in each section.
Moreover, force F is not necessarily constant.
Force to pull the spring increases when the spring expands when the spring is pulled.
In a word, force depends on the position.
In this case, power is divided into a slight amount, and the work of each slight section is calculated. The entire work is calculated adding them up.
These are synthesized, therefore the definition of work is as follows.
It is understood that work shows "Effect that force causes" from the expression of this definition.
If the object doesn't move even if big power is added, work is 0.
If the object moved distance s by the effect of force, the magnitude in the effect is Fs.
Because it is a product of force and the distance, the unit of work is Nm.
However, because work is an important concept, J(joule) is specially applied.