| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.07 |
| Score | 0% | 61% |
| 70.83 lbs. | |
| 6.2 lbs. | |
| 11 lbs. | |
| 6 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 will increase the mechanical advantage of this inclined plane?
lower the force acting at the blue arrow |
|
lengthen the ramp |
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shorten the ramp |
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increase the force acting at the blue arrow |
The mechanical advantage (MA) of an inclined plane is the effort distance divided by the resistance distance. In order to increase mechanical advantage, this ratio must increase which means making the effort distance longer and this can be accomplished by lengthening the length of the ramp.
Which of the following is not a type of structural load?
occupancy load |
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live load |
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wind load |
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dead load |
Dead load is the weight of the building and materials, live load is additional weight due to occupancy or use, snow load is the weight of accumulated snow on a structure and wind load is the force of wind pressures against structure surfaces.
What type of load is sudden and for a relatively short duration?
dynamic load |
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non-uniformly distributed load |
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impact load |
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concentrated load |
A concentrated load acts on a relatively small area of a structure, a static uniformly distributed load doesn't create specific stress points or vary with time, a dynamic load varies with time or affects a structure that experiences a high degree of movement, an impact load is sudden and for a relatively short duration and a non-uniformly distributed load creates different stresses at different locations on a structure.
Tension is a force that does which of the following?
heats up an object |
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slows an object |
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compacts an object |
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stretches an object |
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.