Your Results | Global Average | |
---|---|---|
Questions | 5 | 5 |
Correct | 0 | 2.65 |
Score | 0% | 53% |
Which of the following statements about drag is false?
slower objects experience more drag than faster objects |
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the amount of drag depends on the speed of an object |
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the amount of drag depends on the shape of an object |
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drag occurs during movement through a fluid |
Drag is friction that opposes movement through a fluid like liquid or air. The amount of drag depends on the shape and speed of the object with slower objects experiencing less drag than faster objects and more aerodynamic objects experiencing less drag than those with a large leading surface area.
An inclined plane increases ___________ to reduce ____________.
distance, power |
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force, power |
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force, distance |
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distance, force |
An inclined plane is a simple machine that reduces the force needed to raise an object to a certain height. Work equals force x distance and, by increasing the distance that the object travels, an inclined plane reduces the force necessary to raise it to a particular height. In this case, the mechanical advantage is to make the task easier. An example of an inclined plane is a ramp.
0.75 | |
-1 | |
1.33 | |
1 |
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 4 and the output radius (where the resistance is being applied) is 3 for a mechanical advantage of \( \frac{4}{3} \) = 1.33
For a hydraulic system, pressure applied to the input of the system will increase the pressure in which parts of the system?
everywhere in the system |
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the portions of the system at an altitude above the input |
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the portions of the system at an altitude below the input |
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all of these are correct |
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.
The advantage of using a third-class lever is that it increases:
the mechanical advantage of the lever |
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the distance traveled by the load |
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the force applied to the load |
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the speed of the load |
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.