| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.28 |
| Score | 0% | 66% |
The mass of an object correlates to the size of the object but ultimately depends on:
gravity |
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the object's potential energy |
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the object's density |
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the object's weight |
Mass is a measure of the amount of matter in an object. In general, larger objects have larger mass than smaller objects but mass ultimately depends on how compact (dense) a substance is.
| 1800 lbs. | |
| 1196 lbs. | |
| 1203 lbs. | |
| 1200 lbs. |
The mechanical advantage (MA) of a block and tackle pulley is equal to the number of times the effort force changes direction. An easy way to count how many times the effort force changes direction is to count the number of ropes that support the resistance which, in this problem, is 10. With a MA of 10, a 120 lbs. effort force could lift 120 lbs. x 10 = 1200 lbs. resistance.
Concurrent forces:
act in a common plane |
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pass through a common point |
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act in a common dimension |
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act along the same line of action |
Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane.
| 7.5 | |
| 15 | |
| 5 | |
| 4.5 |
The mechanical advantage (MA) of a wedge is its length divided by its thickness:
MA = \( \frac{l}{t} \) = \( \frac{25 in.}{5 in.} \) = 5
Which class of lever offers no mechanical advantage?
none of these, all levers offer mechanical advantage |
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third |
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first |
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second |
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.