| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.11 |
| Score | 0% | 62% |
Velocity is the rate at which an object changes position. What is the formula for velocity?
\(\vec{v} = { t \over \vec{d} } \) |
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\(\vec{v} = { \vec{d} \over t } \) |
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none of these |
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\(\vec{v} = \vec{d}t \) |
Velocity is the rate at which an object changes position. Rate is measured in time and position is measured in displacement so the formula for velocity becomes \(\vec{v} = { \vec{d} \over t } \)
Which of the following does not represent the freezing point of water?
273K |
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32°F |
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0°F |
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0°C |
The Fahrenheit scale fixes the freezing point of water at 32°F, the Celsuis scale at 0°C, and the Kelvin scale at 273K.
Acceleration is the rate of change of velocity per unit of time. Which of these is the formula for acceleration?
\(\vec{a} = \Delta \vec{v} t \) |
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\(\vec{a} = { t \over \Delta \vec{v} }\) |
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\(\vec{a} = { \vec{v} \over t }\) |
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\(\vec{a} = { \Delta \vec{v} \over t }\) |
Acceleration is the rate of change of velocity per unit of time. In physics, the delta symbol (\(\Delta\)) represents change so the formula for acceleration becomes \(\vec{a} = { \Delta \vec{v} \over t }\)
Water freezing or boiling is an example of which of the following?
heating |
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phase transition |
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cooling |
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sublimation |
A substance undergoes a phase transition when it moves from one state of matter to another, for example, when water freezes or boils.
Which of the following describes the Earth's mantle?
primarily solid |
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liquid |
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solid |
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primarily liquid |
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.