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Starter Pick up a sheet & write your Name & Period on BOTH sides!

Starter Pick up a sheet & write your Name & Period on BOTH sides!. 12/2 In a complete sentence(s) tell me what you (& group, if applicable) have accomplished/finished & what you have left to do on your seige engine project/report.

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Starter Pick up a sheet & write your Name & Period on BOTH sides!

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  1. StarterPick up a sheet & write your Name & Period on BOTH sides! 12/2 In a complete sentence(s) tell me what you (& group, if applicable) have accomplished/finished & what you have left to do on your seige engine project/report. Ex. I & ….., have completed….. on our trebuchet. We need to still do ….

  2. 12/2/13 We will Identify simple machines and evaluate how they can make work simpler. I will Generate the formulas for mechanical advantage & efficiency that come about from using simple machines.

  3. So far… is about… Work-Energy Theorem Kinetic Energy Energy Work Power Potential Energy Heat Can be enhanced by Mechanical Energy Mechanical Advantage Gravitational P.E. Occurs when Elastic P.E. Increases Through use of Energy Transformations Efficiency Simple machines

  4. So far… is about… Work-Energy Theorem Which states…whenever work is done, energychanges

  5. So far… is about… Work-Energy Theorem Kinetic Energy Energy Work Power Potential Energy Heat Can be enhanced by Mechanical Energy Mechanical Advantage Gravitational P.E. Occurs when Elastic P.E. Increases Through use of Energy Transformations Efficiency Simple machines

  6. So far… Kinetic Energy (energy of motion) Energy Potential Energy (energy of position) Formula: KE= ½ mv2 Units = Joules (J) Formula: PE = mgh Units = Joules (J)

  7. Kinetic Energy (energy of motion) Energy Potential Energy (energy of position) Mechanical Energy ME= PE + KE

  8. On back of UO Think of some examples of KE & PE situations that will help you remember the difference!

  9. Today Work-Energy Theorem Work Formula: W = F x d Units = Joules (J) (Newton-meter)

  10. Today Work-Energy Theorem Work Can be enhanced by Through the use of Efficiency Simple machines which increases Which increases Mechanical Advantage

  11. The Simple Machines

  12. Simple Machines • A machine is a device that helps make workeasier to perform by accomplishing one or more of the following functions: • transferring a force from 1 place to another, • changing the direction of a force, • increasing the magnitude of a force, or • increasing the distance or speed of a force.

  13. Simple Machines

  14. Today Work-Energy Theorem Work Can be enhanced by Through the use of Efficiency Simple machines which increases Which increases Mechanical Advantage

  15. Mechanical Advantage Mechanical advantage: ratio of output/input • For machines that increase force: • MA = output force / input force (Fo/ Fi ) • If Fo > Fi; machine MA >1. • If a machine increases an input force of 10 pounds to an output force of 100 pounds, the machine has a mechanical advantage (MA) of 10. • For machines that increase distance • MA = output distance /input distance (do/ di ) • Nomachine can increaseboth the magnitude and the distance of a force at the same time.

  16. Mechanical Advantage of Simple Machines Mechanical Advantage = OUTPUT INPUT

  17. MA Problems (MA = Fo/Fi) • A machine uses an input force of 200 Newtonsto produce an output force of 800 Newtons. What is the mechanical advantage of this machine? F i F o MA 2. A machine is required to produce an output force of 600 Newtons. If the machine has a mechanical advantage of 6, what input force must be applied to the machine? F i F o MA 3. A machine with a mechanical advantage of 2.5 requires an input force of 120 Newtons . What output force is produced by this machine F i F o MA

  18. Today Work-Energy Theorem Work Can be enhanced by Through the use of Efficiency Simple machines which increases Which increases Mechanical Advantage

  19. Efficiency Efficiency = Work Input x 100% = Fi x di x 100% Work Output Fox do There is NO such thing as a 100% efficient machine BECAUSE?

  20. Efficiency = Work Input x 100%Work Output • A machine uses a work input 200 Joules & it’s work output is 500 Joules What is the efficiency of this machine? Wi Wo E % 2. A machine produces 650 Joules of work. If the machine is 75% efficient, what amount of work must be input? Wi Wo E % 3. A machine that has 250 Joules of work input and is 82% efficient releases how much work? Wi Wo E %

  21. Today Work-Energy Theorem Work Can be enhanced by Through the use of Efficiency Simple machines which increases Which increases Mechanical Advantage

  22. Closure • On back of UO add & arrange information in a way that will help YOU, compare your info & arrangement with your neighbor.

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