| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.93 |
| Score | 0% | 59% |
Power is the rate at which:
work is done |
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friction is overcome |
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potential energy is converted into kinetic energy |
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input force is transferred to output force |
Power is the rate at which work is done, P = w/t, or work per unit time. The watt (W) is the unit for power and is equal to 1 joule (or newton-meter) per second. Horsepower (hp) is another familiar unit of power used primarily for rating internal combustion engines. 1 hp equals 746 watts.
Collinear forces:
act in a common plane |
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pass through a common point |
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act along the same line of action |
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are unrelated to each other |
Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane.
According to Boyle's law, for a fixed amount of gas kept at a fixed temperature, which of the following are inversely proportional?
pressure, volume |
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volume, mass |
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pressure, density |
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density, volume |
Boyle's law states that "for a fixed amount of an ideal gas kept at a fixed temperature, pressure and volume are inversely proportional".
Which class of lever offers no mechanical advantage?
third |
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second |
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first |
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none of these, all levers offer mechanical advantage |
A third-class lever is used to increase distance traveled by an object in the same direction as the force applied. The fulcrum is at one end of the lever, the object at the other, and the force is applied between them. This lever does not impart a mechanical advantage as the effort force must be greater than the load but does impart extra speed to the load. Examples of third-class levers are shovels and tweezers.
A truck is using a rope to pull a car. Tension in the rope is greatest in which of the following places?
in the middle |
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tension is equal in all parts of the rope |
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near the car |
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near the truck |
Tension is a force that stretches or elongates something. When a cable or rope is used to pull an object, for example, it stretches internally as it accepts the weight that it's moving. Although tension is often treated as applying equally to all parts of a material, it's greater at the places where the material is under the most stress.