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25 Cards in this Set
- Front
- Back
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What is transferred when work is done?
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Energy is the ability to do work.
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Which is an example of work being done in a scientific sense?
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Lifting a box is work because it applies a force in the same direction of motion.
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What is a sign that work is being done?
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Work is done when there is motion along with a force.
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When you climb stairs and then walk down a hallway, in which direction is the work done?
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upward
Work is done when you walk up the stairs because you are applying a force in the same direction as your movement. |
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What is the scientific formula for work?
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W = F x d
Feedback: Work equals force times distance. |
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The unit for work is a joule, which is equal to __________.
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N x m
A joule is equal to 1Nm. |
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Power is measured by which units?
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watts
Watts measure power. |
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What happens to the amount of power expended when you are climbing stairs and then climb faster?
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It increases.
When you go faster up the stairs, you increase the power expended. |
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When the pyramids were built, blocks were lifted from a quarry and moved across the desert. When was work done in a scientific sense?
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lifting the blocks
Work was done when the blocks were lifted. |
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A 5,000 N block was lifted 10 m. How much work was done?
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50 000 J
5,000 N being applied over 10 m results in 50,000 J. |
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Section 2: Using Machines
How do input force and output force relate to each other? Feedback: Input force is always equal to output force. |
They are the same.
Input force is always equal to output force. |
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What happens to the total amount of work done when you use a machine compared to not using a machine?
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It stays the same.
Feedback: By using a machine, you do not change work. You just make it easier to do. |
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Mechanical advantage is equal to __________.
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output force divided by input force
Mechanical advantage measures the output force divided by the input force. |
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What is the mechanical advantage if 50 J are put in and 200 J are produced?
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4
For this machine, it multiplies the input force by 4, which is its mechanical advantage. |
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The efficiency of all machines is __________.
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less than 100 percent
All machines lose energy to friction and thus are less efficient than 100%. |
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Section 3: Simple Machines
Name the four simple machines. |
inclined plane, lever, wheel and axle, and pulley
The four basic simple machines are the inclined plane, the lever, the wheel and axle, and the pulley. |
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Which simple machines are found on a hammer?
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plane and lever
The arm of the hammer is the lever, and the claw of the hammer is a plane. |
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A ramp in a building is an example of which machine?
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A ramp is an inclined plane.
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Using an inclined plane allows you to apply __________.
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An inclined plane allows you to input a lesser force than you would without the plane.
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A chisel is an example of which machine?
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A chisel is a wedge.
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A drill bit is an example of which type of machine?
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A drill bit is an example of a screw.
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What does a screw consist of?
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Screws are an inclined plane wrapped around a cylinder.
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On what point does a lever pivot?
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Levers pivot on a fulcrum.
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Which of the following do you think a wheel and axle is most closely related to?
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A wheel and axle is a circular lever.
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Using several pulleys together is known as a __________.
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Pulleys combined together make up a pulley system.
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