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28 Cards in this Set
- Front
- Back
In science, work is accomplished when...
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a force acts on an object as it moves through a distance.
14A |
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Formula for work...
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w=f x d
14A |
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a newton-meter is also a...
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joule (which is also kg x m2
_______ s2 ) 14A |
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Things that make work easier that have only one or two parts...
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simple machines
14A |
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Machines can do these 3 things, but never this...
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can do: increase the amount of force, change the direction of force, and change speed of force
can't do: increase the amount of work done or energy expended 14A |
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a bar that turns on a point...
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lever. The point is the fulcrum. 14A
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Law of Moments...
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w1d1 =w2d2
14A |
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In first class lever, where is the fulcrum?
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between the effort on one end and the resistance on the other
14A |
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Force multiplying ability...
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mechanical advantage
14A |
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mechanical advantage formula..
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ratio of resisting force /applied force
or ratio of distance effort applied/distance resistance moves 14A |
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In a second class lever, the resistance is...
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between the effort on one end and the fulcrum on the other.
14A |
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In a third class lever, the resistance is...
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on one end, the effort in the middle, and the fulcrum on the other end. 14A
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Name the class of these levers: wheelbarrow, biceps, seesaw.
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second, third, first
14A |
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This modified lever overcomes the limited distance that a resistance can be moved with a lever...
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wheel and axle
14B |
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A single fixed pulley doesn't give you any mechanical advantage but it does...
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change the direction of force.
14B |
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A single moveable pulley gives you an advantage of...
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2 (but the rope must be pulled twice as far as the weight rises)
14B |
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An arrangement of fixed and moveable pulleys...
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block and tackle
14B |
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To find the mechanical advantage in a block and tackle...
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count the number of ropes supporting the resistance.
14B |
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Distance principle...
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any reduction in the effort force will be paid for by an increased distance through with the force must act 14B
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Inclined planes reduce the ...
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effort to raise a load 14B
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The mechanical advantage of an inclined plane...
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length of incline/height
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Two inclined planes placed bottom to bottom...
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wedge
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An inclined plane wrapped around a cylinder...
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screw
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The distance between two adjacent threads on a screw...
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pitch. (also defined as the distance it moves inward for each turn it is given)
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A machine's actual performance (or ratio of work output to work input)...
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its efficiency
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Rate of doing work...
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Power
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Power formula...
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work/time
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Units for power...
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watts (W)
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