| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.10 |
| Score | 0% | 62% |
For a hydraulic system, pressure applied to the input of the system will increase the pressure in which parts of the system?
everywhere in the system |
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the portions of the system at an altitude below the input |
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all of these are correct |
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the portions of the system at an altitude above the input |
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.
Which of the following will increase the mechanical advantage of a second-class lever?
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 |
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move the object being lifted closer to the fulcrum |
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decrease the length of the lever |
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.
| 9 | |
| 7.7 | |
| 10.5 | |
| 7 |
The mechanical advantage (MA) of a wedge is its length divided by its thickness:
MA = \( \frac{l}{t} \) = \( \frac{14 in.}{2 in.} \) = 7
Which of the following statements about this pulley configuration is false?
Mechanical advantage is the number of ropes that support the resistance |
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Changes the direction of and multiplies the effort force |
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This is a block and tackle pulley configuration |
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Only multiplies the effort force |
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.
Which of these is the formula for kinetic energy?
\(KE = {1 \over 2}mv^2\) |
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\(KE = {1 \over 2}mh^2\) |
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\(KE = mgh\) |
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\(KE = {m \over v^2 }\) |
Kinetic energy is the energy of movement and is a function of the mass of an object and its speed: \(KE = {1 \over 2}mv^2\) where m is mass in kilograms, v is speed in meters per second, and KE is in joules. The most impactful quantity to kinetic energy is velocity as an increase in mass increases KE linearly while an increase in speed increases KE exponentially.