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Simple Machines
Revision for the simple machine exam
Question | Answer |
---|---|
Machines | A device that makes a pysical task easier. |
Lever | A simple machine that uses the turning effect of a force to make a task easier. |
Examples of First Class Levers | Hammer lifting nails, spoon opening a can |
Examples of Second Class Levers | Wheel barrow, nutcracker |
Examples of Third order Levers | Softball bat, broom |
Speed multiplier | Moves the load through a larger distance than the effort moves in the same time. |
Force multiplier | Moves a heavy load with a small force. |
Inclined plane | A surface that is set at an angle to the horizontal. |
Examples of an inclined plane | Ramp, wedge, screw |
Describe a screw | A ramp cut into the screw is the thread; Distance between the thread is the pitch. |
Examples of wheel & axles | Door knobs, taps, car steering wheels |
Pulley | A simple machine consisting of a single wheel & axle has a groove |
What does a single fixed pulley do? | Changes to direction of the effort. |
Block & tackle | A multiple pulley system used in garages, cranes, whaves, ships. |
Gears | Wheels & axles with teeth |
Describe a bevel gear | Gears at right angles to each other can change vertical motion to horizontal motion. |
Example of bevel gears | Hand operated eggbeater & drills. |
Compound machine | Two or more simple machines |
How do you make a screw easier to use | More threads on the screw; a smaller pitch on the screw; longer arms on the lever. |
Equation to balance a lever | Effort x Effort distance=Load x Load distance |
If I have 4 pulleys and I wish to life a load 1 metre how much rope must I pull through. | 4 metres |
How do you calculate the mechanical advantage of a pulley? | Divide load by the effort |
Components of a First Class Lever | Load Fulcrum Effort |
Components of Second Class Lever | Effort Load Fulcrm |
Components of Third Class Lever | Fulcrum Effort Load |