| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.74 |
| Score | 0% | 55% |
| 46.3 lbs. | |
| 47.7 lbs. | |
| 43.3 lbs. | |
| 44.8 lbs. |
This problem describes an inclined plane and, for an inclined plane, the effort force multiplied by the effort distance equals the resistance force multipied by the resistance distance:
Fede = Frdr
Plugging in the variables from this problem yields:
Fe x 12 ft. = 260 lbs. x 2 ft.
Fe = \( \frac{520 ft⋅lb}{12 ft.} \) = 43.3 lbs.
A fixed pulley has a mechanical advantage of:
-1 |
|
0 |
|
1 |
|
2 |
A fixed pulley is used to change the direction of a force and does not multiply the force applied. As such, it has a mechanical advantage of one. The benefit of a fixed pulley is that it can allow the force to be applied at a more convenient angle, for example, pulling downward or horizontally to lift an object instead of upward.
Which class of lever offers no mechanical advantage?
third |
|
none of these, all levers offer mechanical advantage |
|
second |
|
first |
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.
For a hydraulic system, pressure applied to the input of the system will increase the pressure in which parts of the system?
the portions of the system at an altitude above the input |
|
the portions of the system at an altitude below the input |
|
everywhere in the system |
|
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.
A truck is using a rope to pull a car. Tension in the rope is greatest in which of the following places?
in the middle |
|
tension is equal in all parts of the rope |
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near the truck |
|
near the car |
Tension is a force that stretches or elongates something. When a cable or rope is used to pull an object, for example, it stretches internally as it accepts the weight that it's moving. Although tension is often treated as applying equally to all parts of a material, it's greater at the places where the material is under the most stress.