Machines 1. What is Work?

You probably do many kinds of work You may do work for school

You may do work around your house such as mowing the lawn You may work at a job

But these things are not what scientists call work For scientists, work has a special meaning

the use of force to move an object Vocabulary: work the use of force to move an object W = F  D

In order for an action to be work the force used must be in the same direction as the motion

The golfer applies force on the club, which causes the club to move The club applies force on the ball which causes the ball to move

you would not be doing work If you pushed as hard as you could against a big pig and the pig did not move you would not be doing work

Work only happens when an object moves

Lifting a fish out of water is work When you lift the fish you use a force to move the fish

You pull upward on the fish and the fish moves upward

Holding a fish to show it off is not work But when you carry the fish you are using force to keep the fish from falling

The force is an upward force But the fish is moving forward as you (or the bear) walk

Since the force and the motion are not in the same direction So no work is being done

In this unit you will learn more about work and how people make work easier to do