| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.09 |
| Score | 0% | 62% |
| 12 | |
| 3 | |
| 9 | |
| 3.3 |
The mechanical advantage (MA) of a wedge is its length divided by its thickness:
MA = \( \frac{l}{t} \) = \( \frac{6 in.}{2 in.} \) = 3
The measure of how much of the power put into a machine is turned into movement or force is called:
power |
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force multiplication |
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efficiency |
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mechanical advantage |
The efficiency of a machine describes how much of the power put into the machine is turned into movement or force. A 100% efficient machine would turn all of the input power into output movement or force. However, no machine is 100% efficient due to friction, heat, wear and other imperfections that consume input power without delivering any output.
| 5 lbs. | |
| 30 lbs. | |
| 6 lbs. | |
| 70.83 lbs. |
The mechanical advantage of a wheel and axle is the input radius divided by the output radius:
MA = \( \frac{r_i}{r_o} \)
In this case, the input radius (where the effort force is being applied) is 6 and the output radius (where the resistance is being applied) is 5 for a mechanical advantage of \( \frac{6}{5} \) = 1.2
MA = \( \frac{load}{effort} \) so effort = \( \frac{load}{MA} \) = \( \frac{85 lbs.}{1.2} \) = 70.83 lbs.
Which of the following is not a characteristic of a ceramic?
chemically stable |
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high melting point |
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low corrosive action |
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low density |
Ceramics are mixtures of metallic and nonmetallic elements that withstand exteme thermal, chemical, and pressure environments. They have a high melting point, low corrosive action, and are chemically stable. Examples include rock, sand, clay, glass, brick, and porcelain.
For a hydraulic system, pressure applied to the input of the system will increase the pressure in which parts of the system?
the portions of the system at an altitude below the input |
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the portions of the system at an altitude above the input |
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all of these are correct |
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everywhere in the system |
Pascal's law states that a pressure change occurring anywhere in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere. For a hydraulic system, this means that a pressure applied to the input of the system will increase the pressure everywhere in the system.