Work

Work

• Introduction :
• The meaning of work in physics is different from the word we use daily. As work doesn't mean doing the tough jobs but work means that a body have to move with a certain displacement by the act of force.
• 
• Bildunterschrift: fig. (1)

Folie 2

• There are two conditions for work to be done:
• And that can be illustrated by the following two examples :

Folie 3

• 
• 1.The player who lifts weights indeed does work, because the force (aka the player) acting on the weights moves them upwards through a distance in the direction of the force as in fig(2).
• 2. While in fig(3) , the person who pushes the wall does no work, because basically the force acting on the wall fails to move it, so of course the wall remains motionless.
• So we can conclude from that that when a force acts on an object to move it through a certain displacement in the direction of the force, this means that the force does work.
• Bildunterschrift: fig. (2) and fig(3)

Folie 4

• All you need to know about work
• You should keep in mind that (F) is the acting force and (d) is the displacement and if the direction of the force is inclined at an angle then(θ) stands for the measure angle.

Folie 5

• First, we'll start with knowing the factors that affect work:
• Then we'll learn about hoe the angle between displacement and force affect on work:
• Factors affecting work
• The effect of angle on work

Finding work done graphically

• 
• If a constant force act on a body and the force and displacement move in te same diretion the the θ=o as shown in the opposite figure.
• So when as we see in the opposite graph there is a straight line parallel to the displacement axis.
• So since W=Fd
• Therefore, Work(graphically) =length x width=area

Folie 7

• Don't forget!!

Folie 8

• Then let's wrap up this summary with some exercises so you can test your understanding and knowledge?
• Exercise on Work