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SIMPLE MACHINES

SIMPLE MACHINES. SIMPLE MACHINES. Slide 1. SIMPLE MACHINES. The Six Simple Machines are: 1 . Lever 2. Wheel and Axle 3. Inclined Plane 4. Wedge 5. Pulley 6. Screw. Slide 2. What is a Simple Machine?. A simple machine has few or no moving parts.

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SIMPLE MACHINES

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  1. SIMPLE MACHINES SIMPLE MACHINES

  2. Slide 1 SIMPLE MACHINES • The Six Simple Machines are: 1. Lever 2. Wheel and Axle 3. Inclined Plane 4. Wedge 5. Pulley 6. Screw

  3. Slide 2 What is a Simple Machine? • A simple machine has few or no moving parts. • Simple machines make work easier

  4. Slide 3 Science Terms to Know • Force is Push or Pull • Work = Force x distance • W = Fd • Unit of Work is the Joule or J • Power = Work divided by Time • P = W/t • Unit of Power is a Watt or W

  5. Slide 4 Wheels and Axles • The wheel and axle are a simple machine • The axle is a rod that goes through the wheel which allows the wheel to turn • Gears are a form of wheels and axles • Wheels on your bike are wheels and axle

  6. Pulleys Slide 5 • Pulleys are wheels and axles with a groove around the outside • A pulley needs a rope, chain or belt around the groove to make it do work • Flagpole uses a pulley to raise the Flag

  7. Slide 6 Inclined Planes • An inclined plane is a flat surface that is higher on one end • Inclined planes make the work of moving things easier • Ramp is a type of inclined plane

  8. Slide 7 Inclined Plane • Less force is needed to move an object from one height to another using an inclined plane than is needed to lift the object. • As the inclined plane becomes longer, the force needed to move the object becomes smaller.

  9. Slide 8 Using Inclined Planes • Imagine having to lift a box weighing1,500 Nto the back of a truck that is1 moff the ground. • You would have to exert a force of1,500 N,the weight of the box, over a distance of1 m, which equals1,500 Jof work. Remember:W = Fd Work = 1,500N x 1meter = 1,500J

  10. Slide 9 Using Inclined Planes • Now suppose that instead you use a 5-mlong ramp. • The amount of work you need to do does not change. • You still need to do 1,500 J of work. However, the distance over which you exert your force becomes 5 m.

  11. Slide 10 So how much Force are you using? • If you do1,500 Jof work by exerting a force over5 m, the force you push with is only300 Ninstead of 1,500N if you pushed on flat ground • The Equation to use is: (J) (m) F = 1,500 5 = 300N

  12. Slide 11 Wedges • Two inclined planes joined back to back. • Wedges are used to split things.

  13. Slide 12 Wedges in Your Body • Your front teeth are wedge shaped • The teeth of meat eaters, or carnivores, are more wedge shaped than the teeth of plant eaters, or herbivores

  14. Screws Slide 13 • A screw is an inclined plane wrapped around a shaft or cylinder. • The inclined plane allows the screw to move itself when rotated.

  15. Lever Slide 14 • A lever is any rigid rod or plank that pivots, or rotates, about a point. • The point about which the lever pivots is called a fulcrum. • Input Force – is the force being applied by YOU…. • Output Force- is the force that the MACHINE does Fulcrum

  16. What are Input and Output forces of Lever? Slide 15 • Input force: the distance from the Fulcrum to: F-effort – (YOU) • Output force: the distance from the Fulcrum to: F- load – (OBJECT) F – effort/YOU Input force Output force F-load/Object Fulcrum

  17. Lever • Are you confused yet? Remember this to help you: • Input force is the same as F- effort Who is the input force or the F-effort? 2. Output force is the same as F- load = Simple Machine What is the simple machine in this example? The Golfer The Golf club

  18. Slide 16 Levers- First Class • In a first class lever the fulcrum is in the middle and the F- load and F-effort are on either side • Think of a see-saw or Scissors

  19. Levers- Second - Class Slide 17 • In a second class lever the fulcrum is on one end, with the F-load in the middle and F-effort is on other end • Think of a wheelbarrow F- load F-effort Fulcrum

  20. Slide 18 Levers- Third - Class • In a third class lever the fulcrum is again at the end, but the F- effort is in the middle and F-load is on the other end • Think of a pair of tweezers

  21. Mechanical Advantage or MA of a Lever Slide 19 • What is it? • It is how much larger is the Output Force compared to Input force • The higher the MA, the less force you need to use to get the job done • The amount of Work you do doesn’t change, ONLY the amount of Force you need to use to get the job done

  22. Slide 20 How to calculate the MA of Lever? • Using the distance from Fulcrum to Input and Output Force • Mechanical Advantage = Input force (cm) of lever Output force (cm) MA = 1/5 MA = 5

  23. How else can you calculate the MA ? Slide 21 • Use the following MA Equation: • Mechanical advantage = Output force or Fout Input force or Fin MA = Fout Fin • Calculate this problem: To open a can of soup you apply a force of 50N on the can opener. The can opener applies a force of 750N on the can of soup. What is the Mechanical Advantage of the can opener?

  24. Answer: * MA = Fout = 750N = 15 Fin 50N * 750 divided by 50 = 15 * The MA of the can opener is 15 * The higher the MA, the less work you need to do…!!!!!!

  25. Slide 22 What is the Efficiency of a Machine? • Efficiency is comparing the amount of work you do compared to the amount of work the machine does • When a machine is efficient, you don’t have to do as much work

  26. Slide 23 What is the Efficiency Equation? • Efficiency is measured in % • Efficiency = Work out X 100% = Work in eff = Wout x 100% = Win • Problem: You do 100J of work pulling a nail out with a hammer. If the hammer does 70J of work, what is the hammer’s efficiency?

  27. Answer: • eff = Wout = 70J = 70% Win 100J • Divide 70 by 100 = .70 x 100 = 70% • Therefore, the hammer is 70% efficient

  28. Slide 24 Simple Machines • Simple Machines can be put together in different ways to make complex machines The Ultimate Machine

  29. Slide 25Review Questions Question Number 1 • Name this Simple machine Inclined Plane Or Wheel and Axle

  30. Slide 26Question Number 2 • Which type of lever is this? • First – Class • Second – Class • Third - Class Third-class lever

  31. Slide 27Question Number 3 • All 3 pictures are an example of which Simple machine? Lever

  32. Slide 28Question Number 4 • Which simple machines do you see in this picture? Inclined Plane Wheeland Axle

  33. Slide 29Question Number 5 • A can opener is an example of First - Class Lever? • True or False Effort True In the First-class lever the Fulcrum is in middle Fulcrum Load

  34. Slide 30 Slide 26 push pull • Fill-in-the-Blank 6. Force is ______ or _______ 7. Work = ______ x _________ 8. W = ____ 9. Unit of _______is the Joule or J • Power = ______divided by 11. P = _____ 12. Unit of Power is a___________ force distance Fd work time work W/t Watt or W

  35. Slide 31Questions It is how much larger is the Output Force compared to Input force 13.What is the Mechanical Advantage or MA? 14. Write the MA equation: Mechanical Advantage = Output force or Fout Input force or Fin MA = Fout Fin

  36. Slide 32Questions Efficiency is comparing the amount of work you do compared to the amount of work the machine does 15. Explain what is efficiency? 16. What is the efficiency equation? BONUS QUESTION: What is the ultimate Machine? SIMPLE MACHINES VIRTUAL QUIZ – TAKE THE QUIZ Efficiency = Workout X 100 = ____% Workin eff = Wout X 100 = Win Mustang Fastback

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