| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.06 |
| Score | 0% | 61% |
| 15 lbs. | |
| 12 lbs. | |
| 20 lbs. | |
| 17.5 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 10 and the output radius (where the resistance is being applied) is 5 for a mechanical advantage of \( \frac{10}{5} \) = 2.0
MA = \( \frac{load}{effort} \) so effort = \( \frac{load}{MA} \) = \( \frac{35 lbs.}{2.0} \) = 17.5 lbs.
What is the first step to solving a problem where multiple forces are acting on an object?
calculate the total force |
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calculate potential energy |
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calculate the net force |
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calculate kinetic energy |
In mechanics, multiple forces are often acting on a particular object and, taken together, produce the net force acting on that object. Like force, net force is a vector quantity in that it has magnitude and direction.
An inclined plane increases ___________ to reduce ____________.
distance, force |
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force, power |
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distance, power |
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force, distance |
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.
| 2 | |
| 9 | |
| 6 | |
| 6.6 |
The mechanical advantage (MA) of a wedge is its length divided by its thickness:
MA = \( \frac{l}{t} \) = \( \frac{12 in.}{2 in.} \) = 6
Assuming force applied remains constant, which of the following will result in more work being done?
moving the object with more acceleration |
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moving the object with more speed |
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moving the object farther |
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increasing the coefficient of friction |
Work is accomplished when force is applied to an object: W = Fd where F is force in newtons (N) and d is distance in meters (m). Thus, the more force that must be applied to move an object, the more work is done and the farther an object is moved by exerting force, the more work is done.