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 Read each slide carefully.  Record notes on notebook paper.  Give your notes a title: “Work Notes”  Write the title of each page in which you will record notes and underline it.  When you see this indicates that you should write the information beside it.  Underline and highlight new vocabulary words. 2

 Work is done when a force causes an object to move a distance in the direction of the applied force. Work=Force x Distance If the object doesn’t move by the force, no work is done 3 Girl pushes the box work is done! She’s working really hard, but the car is not moving. No work is done here. What about this guy? Is he doing work as he carries his laundry to his room?

1. A scientist delivers a speech to an audience of his peers. 2. A body builder lifts 350 pounds above his head. 3. A mother carries her baby from room to room. 4. A father pushes a baby in a carriage. 5. A woman carries a 20 kg grocery bag to her car? 4

No  A scientist delivers a speech to an audience of his peers. No Yes  A body builder lifts 350 pounds above his head. Yes No  A mother carries her baby from room to room. No Yes  A father pushes a baby in a carriage. Yes No  A woman carries a 20 km grocery bag to her car? No 5

 No movement (even if there is force)=NO work is done  No work is done if you are just carrying an object around  If an object is moving but no force is applied NO work is done (ball flying through the air)  Work is only done when a force causes an object to move a distance. 6

Work = Force x Distance  The unit of force is newtons (N)  The unit of distance is meters (m)  The unit of work is newton-meters  One newton-meter is equal to one joule  So, the unit of work is a joule (J) 7

Work = Force x Distance Calculate: If a man pushes a lawn mower 10 meters with a force of 20 N, how much work has he done? 8

Work = Force x Distance 200 joules Calculate: If a man pushes a lawn mower 10 meters with a force of 20 N, how much work has he done? 200 joules (W = 20N x 10m) 9

 What if you are given work and asked to find force or distance? Cover up the variable you are trying to find and then solve what’s left. 10 F D W

 You did 10J of work lifting a 10- newton book, how high did you lift the book? 11 F D W

More force= more work Less force=less work More distance(force same)=more work Work=Force x Distance 12 Vs.

A ramp decreases the force required to lift an object but increases the distance over which the force is applied. AMOUNT The work is easier but the AMOUNT of work done does not change (assuming there’s no friction) The amount of work done with or without a ramp is the same. 13

Steeper slope=more force but less distance so…. AMOUNT same The AMOUNT of work is the same assuming no friction. 14

 Other simple machines such as pulley’s, levers, and wheel and axles affect work in the same way. They decrease force and increase distance making the work easier but the amount of work done does not change.