| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.72 |
| Score | 0% | 74% |
A ramp is an example of which kind of simple machine?
inclined plane |
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first-class lever |
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none of these |
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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.
Which of the following is not a characteristic of a ceramic?
low density |
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chemically stable |
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low corrosive action |
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high melting point |
Ceramics are mixtures of metallic and nonmetallic elements that withstand exteme thermal, chemical, and pressure environments. They have a high melting point, low corrosive action, and are chemically stable. Examples include rock, sand, clay, glass, brick, and porcelain.
| 10.94 lbs. | |
| 21.88 lbs. | |
| 65.63 lbs. | |
| 87.5 lbs. |
To balance this lever the torques on each side of the fulcrum must be equal. Torque is weight x distance from the fulcrum so the equation for equilibrium is:
Rada = Rbdb
where a represents the left side of the fulcrum and b the right, R is resistance (weight) and d is the distance from the fulcrum.Solving for Rb, our missing value, and plugging in our variables yields:
Rb = \( \frac{R_ad_a}{d_b} \) = \( \frac{35 lbs. \times 5 ft.}{8 ft.} \) = \( \frac{175 ft⋅lb}{8 ft.} \) = 21.88 lbs.
| 2.2 | |
| 1 | |
| 2 | |
| 3.5 |
The mechanical advantage (MA) of a wedge is its length divided by its thickness:
MA = \( \frac{l}{t} \) = \( \frac{4 in.}{2 in.} \) = 2
When all forces acting on a system cancel each other out, this is called:
equilibrium |
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rest |
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stasis |
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potential energy |
When a system is stable or balanced (equilibrium) all forces acting on the system cancel each other out. In the case of torque, equilibrium means that the sum of the anticlockwise moments about a center of rotation equal the sum of the clockwise moments.