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40 Cards in this Set
- Front
- Back
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A device that makes work easier |
machine |
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The number of times a machine multiplies the applied force |
mechanical advantage |
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The product of a force and the distance through which it acts |
work |
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The SI unit of work |
joule |
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The rate at which work is done |
power |
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The SI unit of power |
watt |
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List the six simple machines |
lever, pulley, screw, wedge, inclined plane, wheel and axle |
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The force that is applied to a machine |
input force |
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The force that is exerted by a machine |
output force |
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A bar that is free to rotate around a point |
lever |
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The pivot point of a lever |
fulcrum |
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The work that is done on a machine |
input work |
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The work that is done by a machine |
output work |
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The ratio of work output to work input |
efficiency |
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List three ways that machines make work easier |
change the amount of force, the direction of the force or the distance through which a force acts |
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A teeter totter (see saw) is an example of which class of lever? |
first class |
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A wheel barrow is an example of which class of lever? |
second class |
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A baseball bat is an example of which class of lever? |
third class |
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In which class of lever is the input force applied between the fulcrum and the output force? |
third class |
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In which class of lever is the fulcrum between the input force and output force |
first class |
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In which class of lever is the output force placed between the fulcrum and the input force |
second class |
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What is the formula for work? |
work = force x distance |
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What is the formula for power? |
power = work divided by time |
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What is the formula for potential energy? |
potential energy = mass X 9.8 X height |
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What is the formula for kinetic energy? |
kinetic energy = 1/2 mass X velocity squared |
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Energy of motion |
kinetic energy |
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Energy that is stored or due to position |
potential energy |
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List the two main kinds of energy |
kinetic and potential |
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List the six forms of energy |
mechanical, chemical, nuclear, heat, electrical, electromagnetic |
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Which form of energy is associated with bonds between atoms? |
chemical energy |
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Which form of energy is associated with the center of atoms? |
nuclear energy |
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Which form of energy is associated with the movement of electrons? |
electrical energy |
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Which form of energy is associated with moving objects? |
mechanical energy |
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Which form of energy is associated with the movement of particles that make up a substance? |
heat |
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What does the law of conservation of energy state? |
energy cannot be created or destroyed; it can be converted from one form to another |
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What is calculated by dividing output force by input force? |
mechanical advantage |
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If the mechanical advantage of a machine is equal to one, what did the machine do? |
It changed the direction of the input force. |
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If the mechanical advantage of a machine is greater than one, what did the machine do? |
It multiplied the applied force. |
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If the mechanical advantage of a machine is less than one, what did the machine do? |
It increased the distance the force acted and the rate at which the work was done. |
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What doesn't any machine have an efficiency of 100%? |
All machines have moving parts that have friction, some of the work must be used to overcome friction. |
