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17 Cards in this Set
- Front
- Back
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(True or False) Friction and motion occur at the same time. |
True |
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(True or False) Graphite crystals can be used as a lubricant. |
True |
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(True or False) In space fluid friction does not exist. |
True |
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(True or False) Sliding friction occurs when an object is pulled over a surface. |
True |
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(True or False) Teflon is used only to prevent sticking in cooking utensils. |
False |
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(True or False) Friction should always be reduced if possible. |
False |
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(True or False) A fluid may either be liquid or gas. |
True |
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The shape that has the least friction in air is |
streamlined |
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To reduce friction in a roller skate wheel, we could use |
a, b, and c |
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Give three examples of desirable friction. |
shoes on sidewalk, brakes, tires on the road |
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Explain why friction is sometimes undesirable. |
Friction decreases the efficiency of all machines. |
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Give three ways friction can be reduced. |
lubrication, shape, and material |
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Sliding friction. Description: ??? Example: ??? |
resistance to motion when pulled over a surface. flat object over a flat surface |
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Rolling friction. Description: ??? Example: ??? |
resistance of a round surface to another surface. ball bearings, wheels, log rollers |
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Fluid friction. Description: ??? Example: ??? |
resistance of a surface to movement through gas or liquid. Cars or planes to air, boats to air or water, submarines to water. |
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A box weighing 18 newtons requires a force of 6 newton to drag it. What is the coefficient of friction? |
0.33 |
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The box is coated with Teflon and now requires a force of 3 newtons to drag it. What is its new coefficient of friction. |
0.16 |
