| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.06 |
| Score | 0% | 61% |
| 8 | |
| 9.5 | |
| 10 | |
| 2 |
The mechanical advantage (MA) of an inclined plane is the effort distance divided by the resistance distance. In this case, the effort distance is the length of the ramp and the resistance distance is the height of the green box:
MA = \( \frac{d_e}{d_r} \) = \( \frac{48 ft.}{6 ft.} \) = 8
A shovel is an example of which class of lever?
third |
|
first |
|
second |
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a shovel is not a lever |
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.
| 19.8 psi | |
| 6.3 psi | |
| 18.8 psi | |
| 9.4 psi |
According to Boyle's Law, pressure and volume are inversely proportional:
\( \frac{P_1}{P_2} \) = \( \frac{V_2}{V_1} \)
In this problem, V2 = 60 ft.3, V1 = 75 ft.3 and P1 = 15.0 psi. Solving for P2:
P2 = \( \frac{P_1}{\frac{V_2}{V_1}} \) = \( \frac{15.0 psi}{\frac{60 ft.^3}{75 ft.^3}} \) = 18.8 psi
| 10 | |
| 0.7 | |
| 3 | |
| -3 |
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 7 and the output radius (where the resistance is being applied) is 10 for a mechanical advantage of \( \frac{7}{10} \) = 0.7
What type of load acts on a relatively small area of a structure?
dynamic load |
|
non-uniformly distributed load |
|
concentrated load |
|
impact load |
A concentrated load acts on a relatively small area of a structure, a static uniformly distributed load doesn't create specific stress points or vary with time, a dynamic load varies with time or affects a structure that experiences a high degree of movement, an impact load is sudden and for a relatively short duration and a non-uniformly distributed load creates different stresses at different locations on a structure.