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# 2009 Planes

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### 2009 Planes

1. 1. <ul><li>S: Inclined planes, wedges, and screws </li></ul><ul><li>H: Review Notes </li></ul>
2. 2. Inclined plane, wedge and screw April 22, 2009
3. 3. Objectives <ul><li>Define inclined plane, wedge and screw </li></ul><ul><li>Calculate their MA </li></ul>
4. 4. Inclined Plane <ul><li>A slope or ramp that goes from a lower to higher level </li></ul><ul><li>It makes moving objects easier. </li></ul>
5. 5. <ul><li>Spreads work over a large distance. </li></ul><ul><ul><li>Long & gradual  easier to push object. </li></ul></ul><ul><ul><li>Short & steep  harder to push object. </li></ul></ul>Run Rise
6. 6. Inclined plane M.A. Height = 3 meters Slope = 15 meters MA = 15 m / 3 m = 5 MA = Length of Slope Height of Plane
7. 7. <ul><li>The trade-off is that an object must be moved a longer distance than if it was lifted straight up, but less force is needed. </li></ul>
8. 8. <ul><li>A wagon trail on a steep hill will often traverse back and forth. </li></ul><ul><li>Modern freeways use winding paths through steep mountain passes. </li></ul>
9. 10. The Wedge <ul><li>A wedge is an inclined plane on its side. </li></ul><ul><li>A wedge is used to split, tighten, or secure a hold. </li></ul><ul><li>If you apply force at one end, the wedge will go between something, in this case an ax splits a piece of wood. </li></ul>
10. 11. Where can we find wedges? <ul><li>Wedges that split: </li></ul><ul><li>Your teeth </li></ul><ul><li>Every time you bite into something, you are using a wedge. </li></ul><ul><li>Wedges that cut: </li></ul><ul><li>A saw </li></ul><ul><li>A knife </li></ul><ul><li>Wedges that tighten: </li></ul><ul><li>A doorstop to keep the door open. </li></ul><ul><li>Wedges that hold things together: </li></ul><ul><li>A nail holds wood to a wall or other wood. </li></ul>
11. 12. Mechanical Advantage: <ul><li>MA = 6 in /2 in = 3 </li></ul>MA = Length of Slope Thickness of Widest End
12. 13. Screw <ul><li>An inclined plane wrapped around a rod or cylinder </li></ul><ul><li>Used to lift materials or bind things together </li></ul>
13. 14. Screws <ul><li>The inclined plane allows the screw to move itself when rotated. </li></ul>
14. 15. mechanical advantage <ul><li>MA = C / P </li></ul><ul><li>without using a screwdriver: </li></ul><ul><li>P = Pitch of screw </li></ul><ul><li>C = Circumference of the head </li></ul><ul><li>using a screwdriver: </li></ul><ul><li>P = Pitch of screw </li></ul><ul><li>C = Circumference of the screwdriver handle </li></ul>
15. 16. The pitch is the distance between threads. The closer together the threads, the greater the mechanical advantage.