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WHAT IS WORK?
What comes to your mind when you hear the word ‘work’? The word work has many meanings. When people ask, “what is your work?” They refer to a job or employment. When people say, “I’ll meet you after work.” They refer to the part of a day devoted to an occupation or undertaking. When your teacher asks, “Have you done your homework?” They refer to the task or activity needed to be accomplished..
In Physics, work is an abstract idea related to energy. When work is done it is accompanied by a change in energy. When work is done by an object it loses energy and when work is done on an object it gains energy.
Work is done if the objec t you push moves a distance in the difference towards which you are pulling it…
Figure 1. A girl pushing a chair & A boy pushing a toy car
No work is done if the force you exert does not make the object move…
Figure 2. A boy pushing a wall
No work is done if the force you exert does not make the object move in the same direction as the force you exerted…
Figure 3. A waiter carrying a tray
Work is done when the force (F) applied to the object causes the object to have a displacement (d) in the same direction as the force applied. The symbol for work is capital W. The work done by a force can be calculated as
W= Fd
CALCULATING WORK
The unit force is Unit of force= kg m/s^2 or newton, N
Hence, the unit for work, W W= Fd
Unit of work= unit of force x unit of displacement
Unit of work = N mUnit of work= Nm or Joules, J
The unit, joule (J) is named after the English Physicist James Prescott Joule. This is also a unit of energy. One (1) Joule I equal to the work done or energy expended in applying a force of one Newton through a distance of one meter.
