SIMPLE MACHINES

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

Slide 2  A simple machine has few or no moving parts.  Simple machines make work easier

Slide 3  F Force is Push or Pull  W Work = Force x distance  W = Fd  Unit of Work is the Joule or J  P Power = Work divided by Time  P = W/t  Unit of Power is a Watt or W

Slide 4  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

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

Slide 6 AAn inclined plane is a flat surface that is higher on one end IInclined planes make the work of moving things easier  Ramp is a type of inclined plane

Slide 7 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.

Slide 8 Imagine having to lift a box weighing 1,500 N to the back of a truck that is 1 m off the ground. You would have to exert a force of 1,500 N, the weight of the box, over a distance of 1 m, which equals 1,500 J of work. Remember: W = Fd Work = 1,500N x 1meter = 1,500J

Slide 9 Now suppose that instead you use a 5-m long 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.

Slide 10 If you do 1,500 J of work by exerting a force over 5 m, the force you push with is only 300 N instead of 1,500N if you pushed on flat ground The Equation to use is: (J) (m)(m) F = 1,500 5 = 300N F = 1,500 5 = 300N

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

Slide 12 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

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.

 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 Slide 14 Fulcrum

Slide 15  Input force: the distance from the Fulcrum to: F-effort – (YOU)  Output force: the distance from the Fulcrum to: F- load – (OBJECT) Input force Output force F – effort/YOU F-load/Object Fulcrum

A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 Golf club The Golfer

Slide 16  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

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 Fulcrum F- load F-effort

Slide 18  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

 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 Slide 19

Slide 20  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

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?

* 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…!!!!!! Answer:

Slide 22  E Efficiency is comparing the amount of work you do compared to the amount of work the machine does WWhen a machine is efficient, you don’t have to do as much work

 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? Slide 23

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

Slide 24 SSimple Machines can be put together in different ways to make complex machines The Ultimate Machine

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

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

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

Slide 28 Question Number 4 Which simple machines do you see in this picture? Inclined Plane Wheel and Axle

Slide 29 Question Number 5 A can opener is an example of First - Class Lever? True or False True In the First- class lever the Fulcrum is in middle Effort L o a d Fulcrum

Slide 26  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___________ Slide 30 push pull f orcedistance Fd work time work W/t Watt or W

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

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