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15 Cards in this Set
- Front
- Back
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How did Archimedes' machines help defeat the Roman navy?
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Archimedes showed people of Syracuse how to use the catapult, levers and mirrors to defeat the Romans.
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____ is effort expended to accomplish a task.
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Work
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What are the two conditions needed to define work?
1 2 |
1. change in position- an object must be moved
2. applied force - you must apply effort |
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What is the equation for work?
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W = force x distance
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If you push an empty cooler on the surface of a picnic table with a 20N force for a distance of 2m, how much work is accomplished?
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20 N x 2m = 40 Nm
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The Nm has a special name..what is it?
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Joule
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one newton-meter = ______
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1 Joule
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____ are devices that make work easier.
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Machines
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Machines with only one or two parts are called __ ___.
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simple machines
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Name the 6 simple machines:
1 2 3 4 5 6 |
1. lever
2. wheel and axle 3. pulley 4. inclined plane 5. wedge 6. screw |
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How do machines make work easier?
1 2 3 |
1. can increase the amt of work a person can exert
2. change the direction of the force 3. change the speed at which the force is applied |
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A simple ____ is a rigid bar capable of turning about a fixed point called a ___.
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lever
fulcrum |
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Give an example of a lever.
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A balance used to weigh things.
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Give the formula for the law of moments:
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w1 x d1 = w2 x d2
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When the law of moment is not met, the seesaw will tend to pivot (move around) on the fulcrum - this is known as ___.
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torque
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