| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.23 |
| Score | 0% | 65% |
| 0 | |
| 12 | |
| 14 | |
| 6 |
The mechanical advantage (MA) of an inclined plane is the effort distance divided by the resistance distance. In this case, the effort distance is the length of the ramp and the resistance distance is the height of the green box:
MA = \( \frac{d_e}{d_r} \) = \( \frac{54 ft.}{9 ft.} \) = 6
Coplanar 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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have opposite dimensions |
Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane.
A truck is using a rope to pull a car. Tension in the rope is greatest in which of the following places?
near the car |
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tension is equal in all parts of the rope |
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near the truck |
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in the middle |
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.
| 3 | |
| 1.43 | |
| 10 | |
| -3 |
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 10 and the output radius (where the resistance is being applied) is 7 for a mechanical advantage of \( \frac{10}{7} \) = 1.43
A block and tackle with four pulleys would have a mechanical advantage of:
2 |
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4 |
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0 |
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1 |
Two or more pulleys used together constitute a block and tackle which, unlike a fixed pulley, does impart mechanical advantage as a function of the number of pulleys that make up the arrangement. So, for example, a block and tackle with three pulleys would have a mechanical advantage of three.