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15.4 outline Simple and Compound Machines Inclined Plane: _____________________________________________________________ Simple machine with __________________________________________ less ____________________________________________________________________________ is exerted and more effort force is multiplied Mechanical advantage of inclined plan _____________________________________________________________________________________ _________ Ex ____________________________________________ that Egyptians used to build pyramids Wedge • Inclined _____________________________________________________ • __________________________________________________________________ – As wedge moves a _______________________________________________________________________ with greater force – Longer and thinner wedge is, ______________________________________________ to overcome resistance • Usually piece of wood or _____________________________________________ end • Made of _________________________________________________ planes – Knife, ax, key, zipper Screw • Inclined ____________________________________________________ bar ( cylinder) to form a spiral – Screw rotate and with each turn ______________________________________________ – Multiplies the effort _________________________________________________________ • Closer threads, __________________________________________________ is exerted and more the force is multiplied. – Wood screw, ________________________________and bolt Lever • Rigid bar that is free to _______________________________________________________ point. • Force is applied on bar by ____________________________________________________________________ and overcomes resistance force. • Fixed point is called ________________________________________ • Is between _________________________________________________________________ ________________ in the case of pulling up a nail with a crowbar • Sometimes is at the ______________________________________________ • ________________________ classes of levers based on _________________________________________ position First Class lever – The first class lever is the one you may be most familiar with. It ___________________________________________________________ ___________________________________________________________ _ – By adjusting how far the fulcrum is from the ___________________________________________________________ ______________________________________________________, the more force is applied » Crowbar, _____________________________________, pliers and oars 2nd class lever • The second class lever is one ______________________________________________________________________________ _ at the other. The load that is to be moved is between them. • This lever is different in how it works ... it causes the load to move in the ____________________________________________ as the force you apply. Just as with a first class lever, how ______________________________________________________________________________ ______________. If you want to move a very large load with a small applied force, you must put the load _______________________________ to the fulcrum. Direction in which you life is _________________________________________ in which load moves. – Doors, wheelbarrow, _____________________________ and bottle openers. – Wheel acts as __________________________________; ___________________________ is the load, ___________________________ force is force applied to handles. – Effort force exerted over distance you lift handles. Load moves much _____________________________ 3rd class lever • The third class lever is the strangest ... and the one you use the _____________________! • The fulcrum is ______________________________________________________________________________ __________________________________________________________________________. This lever _________________________________________ advantage. Regardless of where you apply the force, the force you apply ______________________________________________________________________________ ______________________________________________________________________________ ________________________________________________________________. If you were using this lever to lift an object at a distance, it would require less force to just stand above it and lift it up ... ___________________________________________________________! So why use a third class lever at all? The answer lies in the fact that the load moves in the same direction as the force you apply, which is convenient. So is the ___________________________________________________ • a pair of tweezers or the human mandible. Pulley • A ______________________________________________________ around grooved wheel. – Can ______________________________________________________________ of force – Fixed pulley is ________________________________________________________________________ _ effort force. • Changes the ________________________________________ of effort force • Distance you pull is __________________________ as the distance the object moves. • Moveable pulley: Pulleys can _________________________________________________________________ ___________________ but cannot change direction of effort force. • Get a greater mechanical advantage by ___________________________________ pulleys – Block and tackle Wheel and Axel • Made of two ________________________________________________ sizes – ___________________________ is larger object and turns smaller object – Smaller object is ____________________________. • Wheel always move ______________________________________ than axel • Force is applied to wheel is ____________________________________________________________ than wheel – Bicycle, Ferris wheels, gears, wrenches, doorknobs, steering wheels, water wheels, windmills Compound Machines • Combination or _______________________________________________ machines – car • Wheels and __________________________ • Gearshift ____________________ • ____________________________ gears • ______________________________ lever • _______________________ wheel
