| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.46 |
| Score | 0% | 69% |
The formula \(\vec{F_{g}} = { Gm_{1}m_{2} \over r^2}\) applies to which of Newton's laws?
second law of motion |
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universal gravitation |
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third law of motion |
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first law of motion |
Newton's law of universal gravitation defines gravity: All objects in the universe attract each other with an equal force that varies directly as a product of their masses, and inversely as a square of their distance from each other. Expressed as a formula: \(\vec{F_{g}} = { Gm_{1}m_{2} \over r^2}\) where r is the distance between the two objects and G is the gravitational constant with a value of 6.67 x 10-11.
The hottest of Earth's atmospheric layers is which of the following?
thermosphere |
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mesosphere |
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troposphere |
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stratosphere |
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.
Which of the following is a decomposer?
mosquito |
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pine tree |
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fungi |
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ferret |
Decomposers (saprotrophs) are organisms such as bacteria and fungi that break down the organic matter in the dead bodies of plants and animals into simple nutrients.
Which of the following is not part of the carbon cycle?
decomposition |
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precipitation |
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respiration |
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photosynthesis |
The carbon cycle represents the ciruit of carbon through Earth's ecosystem. Carbon dioxide (CO2) in the atmosphere is absorbed by plants through photosynthesis. Plants then die and release carbon back into the atmosphere during decomposition or are eaten by animals who breathe (respiration) the carbon into the atmosphere they exhale and produce waste which also releases carbon as it decays.
The crust and lithosphere of the Earth is made up of which of the following?
sedimentary rock |
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continents |
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plates |
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metamorphic rock |
The crust and the rigid lithosphere (upper mantle) is made up approximately thirty separate plates. These plates more very slowly on the slightly more liquid mantle (asthenosphere) beneath them. This movement has resulted in continental drift which is the gradual movement of land masses across Earth's surface. Continental drift is a very slow process, occurring over hundreds of millions of years.