| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.91 |
| Score | 0% | 58% |
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 kinetic energy |
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calculate the net force |
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.
A wedge converts force applied to its blunt end into force __________ its inclined surface.
perpendicular to |
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parallel to |
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along |
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opposite 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.
Gear ratio indicates which of the following about two connected gears?
mechanical advantage |
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efficiency |
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work done |
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power conversion |
The mechanical advantage (amount of change in speed or torque) of connected gears is proportional to the number of teeth each gear has. Called gear ratio, it's the ratio of the number of teeth on the larger gear to the number of teeth on the smaller gear. For example, a gear with 12 teeth connected to a gear with 9 teeth would have a gear ratio of 4:3.
| 1.6 | |
| 3 | |
| 0.63 | |
| 5 |
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 8 and the output radius (where the resistance is being applied) is 5 for a mechanical advantage of \( \frac{8}{5} \) = 1.6
Which of the following will increase the mechanical advantage of this inclined plane?
shorten the ramp |
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lower the force acting at the blue arrow |
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lengthen the ramp |
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increase 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.