1. Simple Machines Simple Machines

2. Machine vs. Simple Machine Machine: Any device that makes work easier Simple Machine ◦ A device that does work with only one movement. ◦ There are four main simple machines

3. Advantages of Simple Machines Makes work easier by changing the force you exert in size, direction or both. Help overcome gravity and friction

4. 2 Kinds of Work Work done by the machine (W out ) Work done on the machine (W in ) W out is always smaller than W in due to friction W= f X d (J)

5. Applying Force 2 forces when a machine does work: ◦ Effort Force (F e ): the force applied to the machine ◦ Resistance Force (F r ): the force applied by the machine

6. Mechanical Advantage The number of times a machine multiplies the effort force MA = resistance force = F r effort force F e The higher the MA the lower the effort put in

7. Inclined Plane Flat slanting surface Connects one level to another

8. Modified Inclined Planes: Screw Screw ◦ Inclined Plane wound around a rod

9. Modified Inclined Planes: Wedge  Wedge  Inclined plane that moves  Inclined Plane that cuts

11. Inclined Plane MA Formulas Ideal Mechanical Advantage IMA= de (length of slope) dr (height of slope) D=distance E= effort R=resistance Actual Mechanical Advantage AMA=Fr (mass) Fe (effort) F=force E=effort R=resistance

12. Lever Pivots around a fulcrum which can increase force or increase distance Effort arm Resistance arm

13. Mechanical Advantage of Levers IMA = length of effort arm = Le length of resistance arm Lr  AMA= R E

14. Classes of Levers First Class (EFR) ◦ Ex: seesaw Second Class (FRE) ◦ Ex: Wheelbarrow Third Class (REF) ◦ Tweezers Effort Resistance Fulcrum

15. Pulley Rope passing over a grooved wheel Changes direction of force or amount of force

16. Pulley Can be movable or fixed Block and Tackle: combinations of pulleys to gain a large MA

17. AMA= R (resistance E (effort)  IMA= Number of supporting strings

18. Wheel and Axle Wheel rotating around an axle Ex: Doorknobs, faucets, etc.

19. Mechanical Advantage Mechanical Advantage

20. MA Formula AMA= R E R=Resistance E=Effort IMA= Rw Ra R=Radius w=wheel a= axle