| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.63 |
| Score | 0% | 53% |
Which of the following is not a type of structural load?
live load |
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wind load |
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occupancy load |
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dead load |
Dead load is the weight of the building and materials, live load is additional weight due to occupancy or use, snow load is the weight of accumulated snow on a structure and wind load is the force of wind pressures against structure surfaces.
Which of the following will increase the mechanical advantage of a second-class lever?
move the object being lifted closer to the fulcrum |
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decrease the length of the lever |
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move the object being lifted farther away from the fulcrum |
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move the fulcrum between the force and the object being lifted |
A second-class lever is used to increase force on an object in the same direction as the force is applied. This lever requires a smaller force to lift a larger load but the force must be applied over a greater distance. The fulcrum is placed at one end of the lever and mechanical advantage increases as the object being lifted is moved closer to the fulcrum or the length of the lever is increased. An example of a second-class lever is a wheelbarrow.
A truck is using a rope to pull a car. Tension in the rope is greatest in which of the following places?
near the car |
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tension is equal in all parts of the rope |
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in the middle |
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near the truck |
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.
Boyle's law defines the relationship between pressure and volume as:
\(\frac{P_1}{P_2} = \frac{V_2}{V_1}\) |
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\({P_1}{P_2} = {V_1}{V_2}\) |
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\(\frac{P_1}{P_2} = {V_1}{V_2}\) |
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\(\frac{P_1}{P_2} = \frac{V_1}{V_2}\) |
Boyle's law states that "for a fixed amount of an ideal gas kept at a fixed temperature, pressure and volume are inversely proportional". Expressed as a formula, that's \(\frac{P_1}{P_2} = \frac{V_2}{V_1}\)
Which of the following statements about this pulley configuration is false?
Changes the direction of and multiplies the effort force |
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Mechanical advantage is the number of ropes that support the resistance |
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Only multiplies the effort force |
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This is a block and tackle pulley configuration |
A block and tackle is a combination of one or more fixed pulleys and one or more movable pulleys where the fixed pulleys change the direction of the effort force and the movable pulleys multiply it. The mechanical advantage is equal to the number of times the effort force changes direction and can be increased by adding more pulley wheels to the system. An easy way to find the mechanical advantage of a block and tackle pulley system is to count the number of ropes that support the resistance.