| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.86 |
| Score | 0% | 57% |
Specific gravity is a comparison of the density of an object with the density of:
carbon |
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oil |
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water |
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air |
Specific gravity is the ratio of the density of equal volumes of a substance and water and is measured by a hyrdometer.
A fixed pulley has a mechanical advantage of:
0 |
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1 |
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-1 |
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2 |
A fixed pulley is used to change the direction of a force and does not multiply the force applied. As such, it has a mechanical advantage of one. The benefit of a fixed pulley is that it can allow the force to be applied at a more convenient angle, for example, pulling downward or horizontally to lift an object instead of upward.
A wedge converts force applied to its blunt end into force __________ its inclined surface.
perpendicular to |
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along |
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opposite to |
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parallel to |
The wedge is a moving inclined plane that is used to lift, hold, or break apart an object. A wedge converts force applied to its blunt end into force perpendicular to its inclined surface. In contrast to a stationary plane where force is applied to the object being moved, with a wedge the object is stationary and the force is being applied to the plane. Examples of a wedge include knives and chisels.
Which of the following will increase the mechanical advantage of this inclined plane?
lengthen the ramp |
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increase the force acting at the blue arrow |
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shorten the ramp |
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lower 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 class of lever offers no mechanical advantage?
third |
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first |
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second |
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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.