| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.72 |
| Score | 0% | 74% |
The formula for acceleration is which of the following?
\(\vec{a} = \vec{F} m\) |
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\(\vec{a} = { m \over F }\) |
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\(\vec{a} = { \vec{F} \over m }\) |
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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, \(\vec{F} = m\vec{a}\).
An element in the physical state of __________ maintains a constant volume and shape.
gel |
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solid |
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gas |
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liquid |
An element in a solid state has atoms or molecules that are constricted and do not move freely. Solids maintain a constant volume and shape and exist at a lower temperature than liquids or gases.
An element in the physical state of __________ maintains neither a constant volume nor a constant shape.
plasma |
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solid |
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gas |
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liquid |
The gaseous state occurs at a higher temperature range than the solid and liquid states of the same substance. In this state, molecules flow very freely around each other and will spread out as far as they're able. Gases maintain neither a constant volume nor a constant shape.
Which of the following describes the Earth's mantle?
makes up most of Earth's volume |
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all of these |
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hot |
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dense |
Mantle makes up 84% of the Earth's volume and has an average thickness of approximately 1,800 miles (2,900 km). It is dense, hot, and primarily solid although in places it behaves more like a viscous fluid as the plates of the upper mantle and crust gradually "float" along its circumference.
The hottest of Earth's atmospheric layers is which of the following?
stratosphere |
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troposphere |
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thermosphere |
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mesosphere |
Temperatures again increase with altitude in the thermosphere which is the hottest (4,530 °F / 2,500 °C) atmospheric layer due to direct exposure to the Sun's radiation. However, the gas in this layer is highly diluted so even though the atoms of gas may be very high in temperature, there are too few of them to effectively transfer much heat.