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28 Cards in this Set
- Front
- Back
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How can the efficiency of a machine be improved?
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reduce the friction (by adding a lubricant like oil)
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What are 2 forms of energy?
define them |
potential-stored energy
kinetic-energy in motion |
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eauation for calculating work
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Work = force X distance
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effort force
give example |
the force applied to a machine when machine is used to do work.
the force applied to the machine |
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lever
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a bar that is free to pivot, or turn about a fixrd point
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give 3 examples of wheel and axle
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doorknob, faucets, ice-cream maker
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How are a screw and wedge related to the inclined plane
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The blade of the wedge and the threads of the screw are inclined planes
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give 2 examples of compound machines
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bicycle and scissors
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name the 3 classes of levers
be able to draw them |
1st class
2nd class 3rd class |
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energy
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the ability to cause change
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joule
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the basic unit of energy and work; named for James Prescott Joule
1 joule = a force of 1 newton moving thrugh 1 meter |
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energy
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the ability to do work
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Write the equation for calculating the power of a machine.
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page 202
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mechanical advantage
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the number of times a machine multiplies the effort force applied to it.
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define watt
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how power is measured. A watt is 1 joule per second. named for James Watt.
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When is there a gain in force
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when the mechanical advantage of a machine is greater than 1
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why is a bicycle a compound machine?
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It is made up of 2 or more simple machines. wheel and axle, pulley
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write eauation for finding the mechanicl advantage of a lever.
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resistance force
give example |
the force exerted by a machine to overcome resistance to gravity or friction.
The work the crowbar does to pry open a lid. |
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what 2 factors deterlmine the amount of kinetic energy a moving object has?
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mass and velocity
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write the equation for calculating efficiency
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page 200
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How do you find the radius of a wheel and axle?
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page 192 in book
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Define work in a sentence
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the transfer of energy through motion
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Write equation for finding mechanical advantage of wheel and axle
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page 192
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how do you calculate the mechanical advantage of an inclined plane?
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page 193
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what are the 3 parts of a lever?
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fulcrum, effort arm and resistance arm
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give example of kinetic energy
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runner, bike tire spinning, (anything moving)
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Give example of potential energy
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A flower pot sitting on a ledge. If something makes it fall it changes to kinetic energy
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