| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.92 |
| Score | 0% | 58% |
Which of the following surfaces would have the lowest coefficient of friction?
tile |
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ice |
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leather |
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concrete |
Coefficient of friction (μ) represents how much two materials resist sliding across each other. Smooth surfaces like ice have low coefficients of friction while rough surfaces like concrete have high μ.
Force of friction due to kinetic friction is __________ the force of friction due to static friction.
higher than |
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the same as |
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opposite |
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lower than |
The formula for force of friction (Ff) is the same whether kinetic or static friction applies: Ff = μFN. To distinguish between kinetic and static friction, μk and μs are often used in place of μ.
Which of the following is not a characteristic of a ceramic?
high melting point |
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low density |
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low corrosive action |
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chemically stable |
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.
Which of the following represents how much two materials resist sliding across each other?
static friction |
|
kinetic friction |
|
coefficient of friction |
|
normal friction |
Coefficient of friction (μ) represents how much two materials resist sliding across each other. Smooth surfaces like ice have low coefficients of friction while rough surfaces like concrete have high μ.
| 24.3 psi | |
| 18.2 psi | |
| 14.6 psi | |
| 16.2 psi |
According to Boyle's Law, pressure and volume are inversely proportional:
\( \frac{P_1}{P_2} \) = \( \frac{V_2}{V_1} \)
In this problem, V2 = 25 ft.3, V1 = 45 ft.3 and P1 = 9.0 psi. Solving for P2:
P2 = \( \frac{P_1}{\frac{V_2}{V_1}} \) = \( \frac{9.0 psi}{\frac{25 ft.^3}{45 ft.^3}} \) = 16.2 psi