| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.36 |
| Score | 0% | 67% |
A ramp is an example of which kind of simple machine?
none of these |
|
inclined plane |
|
first-class lever |
|
wedge |
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.
What type of load varies with time or affects a structure that experiences a high degree of movement?
impact load |
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dynamic load |
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concentrated load |
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static 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.
| 2 ft. | |
| 18 ft. | |
| 24 ft. | |
| 6 ft. |
To balance this lever the torques at the green box and the blue arrow must be equal. Torque is weight x distance from the fulcrum so the equation for equilibrium is:
Rada = Rbdb
where a represents the green box and b the blue arrow, R is resistance (weight/force) and d is the distance from the fulcrum.Solving for da, our missing value, and plugging in our variables yields:
da = \( \frac{R_bd_b}{R_a} \) = \( \frac{40 lbs. \times 3 ft.}{20 lbs.} \) = \( \frac{120 ft⋅lb}{20 lbs.} \) = 6 ft.
What type of load is sudden and for a relatively short duration?
dynamic load |
|
concentrated load |
|
impact load |
|
non-uniformly distributed 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.
According to Boyle's law, for a fixed amount of gas kept at a fixed temperature, which of the following are inversely proportional?
volume, mass |
|
density, volume |
|
pressure, density |
|
pressure, volume |
Boyle's law states that "for a fixed amount of an ideal gas kept at a fixed temperature, pressure and volume are inversely proportional".