Power

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GCSE Physics double award notes

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Power

  1. 1. Power GCSE Physics
  2. 2. Some things that are powerful… It is said that power corrupts, but actually it's more true that power attracts the corruptible. The sane are usually attracted by other things than power
  3. 4. Who’d man!!?? <ul><li>World’s Strongest Man Competition </li></ul><ul><li>Atlas Stones </li></ul><ul><li>Work done = Force x distance </li></ul><ul><li>Energy = (160 x 10) x 2 </li></ul><ul><li>= 3,200 J </li></ul><ul><li>Compared to climbing the stairs? </li></ul>Are they more Powerful than you or me?
  4. 5. Learning Intentions <ul><li>By the end of the lesson we will be able to… </li></ul><ul><li>Define the term ‘power’ using it correctly in the context of physics </li></ul><ul><li>Recall the equation for power, including the units </li></ul><ul><li>Calculate power in a number of simple experiments </li></ul>
  5. 6. <ul><li>Page 10 </li></ul><ul><li>The quantity of energy transferred or work done is more useful when we consider how quickly it can happen. </li></ul><ul><li>Power is the rate of doing work </li></ul><ul><li>A construction crane is regarded as powerful if it can lift a heavy steel beam in a short time </li></ul>Power
  6. 7. Calculating Power <ul><li>The equation for power- </li></ul>Power = Work Done Time Taken W t P = / Joule second Watt = / Word Equation Dimensions Units
  7. 9. Example <ul><li>A fork lift truck can raise a load of 315 kg to a height of 2 m in 20 seconds. What is the power developed? </li></ul><ul><li>Work Done = F x d </li></ul><ul><li>= (315 x 10) x 2 = 6300 J </li></ul><ul><li>Power = Energy / Time Taken </li></ul><ul><li>= 6300 / 20 </li></ul><ul><li>= 315 W </li></ul>
  8. 10. You try this one… <ul><li>A mouse of mass 30 g runs up a 2 m curtain in 4 seconds. Calculate its power in Watts </li></ul><ul><li>Work Done = (0.03 x 10) x 2 </li></ul><ul><li>= 0.6 J </li></ul><ul><li>Power = Work Done / Time taken </li></ul><ul><li>= 0.6 / 4 </li></ul><ul><li>= 0.15 W </li></ul>

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