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ch 8 terms adam
adam ciaccio
Question | Answer |
---|---|
Work | occurs when a force causes an object to move in the direction of the force |
Work is ONLY done when ………… | the force is in the same direction that the object is going |
These 2 things must be present in order for work to be occurring | work and force |
What is the work formula ? | W= F x D |
What is the power formula? | P= W/T |
Watt include picture(s) | The unit used to express power |
Machine include picture(s) | a device that helps make work easier by changing the size or direction of a force |
Work Input | the work you do on a machine |
Work Output | The work done by the machine |
When can work output be GREATER than work input? – it can never be greater. | |
(carefully read last paragraph p. 193) | |
“Machines don’t save work” . True or false? Explain your answer | False. The same work is done either way |
Mechanical Advantage –tells you how many times the machine multiplies force | |
Mechanical Advantage formula –MA= output force/input force | |
What are the 6 simple machines ? | Lever, screw, wedge, pulley, wheel and axle, inclined plane |
Lever –simple machine consisting of a bar that pivots at a fixed point | |
Examples of include picture(s) | see saw, kayak, wheel barrow |
Fulcrum –the point on a level where the bar pivots | |
Examples of each of the 3 classes of levers | include picture(s) |
Inclined Plane | simple machine that is a straight, slanted surface |
How do you increase the mechanical advantage of an inclined plane? | the longer the inclined plane is compared with its height, the greater the mechanical advantage |
Examples of Inclined Planes include picture(s) | a ramp |
Wedge | a double inclined plane that moves. |
Examples of Wedges include picture(s) | A knife |
Screws | an inclined plane that is wrapped in a spiral |
Examples Screws include picture(s) | jar lid, screw |
How do you change the mechanical advantage of a screw? | the longer the inclined plane the higher the mechanical advantage |
Wheel & Axle | a simple machine consisting of two circular objects of different sizes |
Examples of Wheel & Axle include picture(s) | water pump |
Pulley –a simple machine consisting of a grooved wheel that holds a rope or a cable | |
Examples of Pulleys include picture(s) | Cable cars |