| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.82 |
| Score | 0% | 56% |
Which of the following describes the Earth's outer core?
liquid |
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makes up most of the Earth's volume |
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solid |
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primarily solid |
The Earth's core is divided into the liquid outer core (1,430 miles or 2,300 km radius) and the solid inner core (745 miles or 1,200 km radius).
Small rocks shed by asteroids and comets that reach the earth are called:
meteoroids |
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meteors |
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shooting stars |
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meteorites |
Smaller rocks shed by asteroids and comets are called meteoroids. When these rocks reach Earth's atmosphere, they burn up in the mesosphere and become meteors. If a meteor manages to reach the Earth, it is called a meteorite.
Which of the following substances gives up positively charged hydrogen ions (H+) when dissolved in water?
solution |
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base |
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alkaline |
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acid |
An acid is a substance that gives up positively charged hydrogen ions (H+) when dissolved in water. A base (alkaline) gives up negatively charged hydroxide ions (OH-) when dissolved in water. pH is a scale that measures of how basic or acidic a solution is. Numbered from 0 to 14, solutions with a pH of 7 are neutral, less than 7 are acidic, more than 7 are alkaline.
Which of the following is not a method of heat transfer?
convection |
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conduction |
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reflection |
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radiation |
Heat is always transferred from warmer to cooler environments through conduction, convection, or radiation.
The formula for acceleration is which of the following?
\(\vec{a} = \vec{F} m\) |
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\(\vec{a} = { \vec{F} \over m }\) |
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\(\vec{a} = { m \over F }\) |
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\(\vec{a} = { m \over \vec{F} }\) |
Newton's second law of motion leads to the formula for acceleration which is a measure of the rate of change of velocity per unit time and, if you solve for positive acceleration, reveals how much net force is needed to overcome an object's mass. The formula for acceleration is \(\vec{a} = { \vec{F} \over m }\) or, solving for force, \(\vec{F} = m\vec{a}\).