1. AIM: ? OBJ: Given notes and activity sheet SWBAT with 70% accuracy DN: ACT: HW:

2. Simple Machines Machines help by making work (W i ) easier. To make work easier, you can reduce the input force (F i ) by increasing the input distance (D i ) you exert (apply). There are six (6) basic kinds of simple machines: inclined plane, wedge, screw, lever, wheel & axle, and pulley.

5. Simple Machines Inclined plane (ramp): flat sloped surface W i = decrease F i x increase D i MA (ramp) = L (ramp) H (ramp)

6. Simple Machines Wedge = two inclined planes (back to back) that can move; produces two output forces (F o ). MA (wedge) = L W

7. Simple Machines Screw = an inclined plane wrapped around a cylinder. MA (screw) = thread length screw length

8. Simple Machines Levers = rigid bar that pivots/rotates on a fixed point. Fulcrum = fixed point that a lever pivots around. In 1 st and 2 nd class levers, input force (F i ) can be reduced by increasing input distance (D i ). MA (lever) = D fulcrum↔Fi D fulcrum↔Fo

9. Simple Machines Types of Levers: http://www.enchantedlearning.com/physics/machines/Levers.shtml http://www.enchantedlearning.com/physics/machines/Levers.shtml First Class Lever: F o F F i change force direction; as fulcrum close to F o, F o increases Example: scissors, pliers, seasaw Second Class Lever: F i F o F same force direction; as fulcrum close to F o, F o increases Example: doors, nutcracker, bottle opener Third Class Lever: F o F i F same force direction; as fulcrum close to F i, F o decreases Example: fishing pole, shovel, baseball bat