1. Inclined Plane  Inclined Plane sloping surface used to raise objects h l

2. Screw  Screw inclined plane wrapped in a spiral around a cylinder

3. Wedge  Wedge a moving inclined plane with 1 or 2 sloping sides

4. Wedge  Zipper 2 lower wedges push teeth together 1 upper wedge pushes teeth apart

5. Problems  How much force must be exerted to push a 450 N box up a ramp that is 3 m long and 1.2 m high? GIVEN: F e = ? F r = 450 N l = 3 m h = 1.2 m WORK : IMA = l ÷ h IMA = (3 m)÷(1.2 m) IMA = 2.5 IMA l h MA FrFr FeFe F e = F r ÷ MA F e = (450 N)÷(2.5) F e = 180 N

6. Compound Machines  Compound Machine combination of 2 or more simple machines

7. Compound Machines  Rube Goldberg Machine Rube Goldberg walks in his sleep, strolls through a cactus field in his bare feet, and screams out an idea for self-operating napkin: As you raise spoon of soup (A) to your mouth it pulls string (B), thereby jerking ladle (C) which throws cracker (D) past parrot (E). Parrot jumps after cracker and perch (F) tilts, upsetting seeds (G) into pail (H). Extra weight in pail pulls cord (I), which opens and lights automatic cigar lighter (J), setting off sky-rocket (K) which causes sickle (L) to cut string (M) and allow pendulum with attached napkin to swing back and forth thereby wiping off your chin. After the meal, substitute a harmonica for the napkin and you'll be able to entertain the guests with a little music.