Simple Machines and Work

Work

• Work is done on an object when the object moves in the same direction in which the force is exerted.

• If no motion occurs then there will be no work.

• Did you do work with your book bag on your back walking to class?

Calculating Work

• Work depends on two things:

1. Force

2. Distance

• Which would require more work:

1. Lifting a 50N potted plant .5 m off the ground to a table or a 100N potted plant the same distance.

Calculating Work

• We can find the work it takes to move objects with the following equation.

W= Force (F) x Distance (d)

• The following unit is used for work:

• Joule (J)

Now, find how much work it would take to move each of the plotted plants.

Calculating Work

How much work would it take to move a 250 N car a distance of 5m?

How much work would it take to lift a 63 N book a distance of 3m?