2. Machines and Mechanical Advantage Archimedes (Greek mathematician, 287 to 212 B.C.) said, “Give me a place to stand and I will move the Earth,” meaning that if he had a lever long enough, he could move the Earth by his own effort

3. Mechanical Advantage (M.A.) the number of times a machine multiplies the input force (F I ) the more times the machine multiplies the input force, the “easier” the job (requires less force by us)

5. MA = Mechanical Advantage F O = Output Force or Load F I = Input Force MA = F O F I Mechanical Advantage formula

6. Example problem using forces What is the mechanical advantage of a machine where an input force of 20 N will put out a force of 180 N? F O = 180N MA = F O 180N/20N 9 F I = 20N F I given formula set up problem answer w/ unit of measurement NO UNIT OF MEASUREMENT RATIO There is NO UNIT OF MEASUREMENT on mechanical advantage, it is simply a RATIO

7. Six Types of Simple Machines basically a ramp has no moving parts decreases the input force needed to move an object but increases the distance necessary to move it 1. Inclined Plane The Inclined Plane Family

9. 2. Wedge an incline plane that moves through something normally made up of two inclined planes

10. 3. Screw an inclined plane that is wrapped around to form a spiral multiplies the input force by increasing the distance

11. 4. Lever a rigid bar that is free to pivot on a fulcrum Three classes of levers –First Class The Lever Family

12. –Second class

13. –Third class the only lever that does NOT multiply the input force but does increase speed and distance of what you are moving

16. 5. Pulley a rope, belt, chain… wrapped around a grooved wheel may change the direction of the force may multiply the effort force to lift heavy loads when using many pulleys

19. 6. Wheel and Axle or Gears a lever or pulley connected to a shaft –the wheel/gear is the larger circle/lever/pulley –the axle is the smaller circle/shaft/axle

20. Compound Machines a combination of two or more simple machines http://www.youtube.com/watch?v=hSI5 HjHOiiY&feature=related