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Work and Power

Work and Power. Work. Work happens when a force moves an object over a distance If the object does not move, no work is done For work to be done, the direction of the applied force must be the same as the direction of the motion. Work. You lift a bag of groceries

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Work and Power

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  1. Work and Power

  2. Work • Work happens when a force moves an object over a distance • If the object does not move, no work is done • For work to be done, the direction of the applied force must be the same as the direction of the motion

  3. Work • You lift a bag of groceries from the trunk of your car • Is work being done? • You are using force to lift the bag of groceries, and the force is in the direction of the motion

  4. Work • You carry a bag of groceries from the car to the kitchen • Is work being done? • You are using force to carry the groceries • Is the force being applied in the direction of the motion?

  5. Calculating Work • Work = force x distance moved • W=FΔd (on your reference table!) • Units of work are N·m, • Also known as the joule • Abbreviated J • Set up the triangle!

  6. Calculating Work Work Force Distance

  7. Work Practice • 60N of force is used to move an object a distance of 4.0m. How much work has been done on the object?

  8. Work Practice • When you pick up your backpack, you do 58J of work to lift it up 1.3m to put it on your back. What is the force on the backpack?

  9. Work Practice • A tow truck tows your car 2200m to the nearest service station. If the truck did 2,970,000J of work to tow the car, what was the force on the car?

  10. Work Practice • A crane lifts a steel beam with 5200J of work. If the force on the beam is 240N, what is the distance the beam has been lifted?

  11. Power

  12. The Power Triangle Work Power Time

  13. Power • Where have you heard of watts before? • Electrical energy • Light bulbs • Can you explain why a bulldozer has more power than a person with a shovel? • Work and Power Tune

  14. Calculating Power • Espen and Deion push a sofa across a room in 16 seconds using 142J of work. How much power did they use?

  15. Calculating Power • KJ uses 72J of work to push a textbook across the table. He uses 432W of power. How long did it take him to move the book?

  16. Calculating Power • Aniké and Alanah move the lab table for 3 seconds using 98W of power. How much work did they do?

  17. Calculating Power • Brynne throws a 12N softball 4m in 1.8s. How much power has she used on the softball?

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