| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.03 |
| Score | 0% | 61% |
Which of the following is not a characteristic of the Sun?
makes up over 99% of the mass of the solar system |
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is composed of hydrogen and helium |
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formed 2.6 billion years ago |
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is a yellow dwarf star |
The Sun is a G-type main-sequence star (G2V) but is informally known as a yellow dwarf star. Composed of 73% hydrogen and 25% helium, the hot plasma that makes up the Sun reaches 9,900°F (5,505°C) at the surface. It formed approximately 4.6 billion years ago and makes up 99.86% of the mass in the solar system.
The formula \(\vec{F_{g}} = { Gm_{1}m_{2} \over r^2}\) applies to which of Newton's laws?
first law of motion |
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universal gravitation |
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third law of motion |
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second 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.
Water coming to a boil on a stove, ice melting, and steam from a cup of coffee are all examples of which of the following?
radiation |
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convection |
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reflection |
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conduction |
Convection is the transfer of heat by the circulation or movement of the heated parts of a liquid or gas.
Which of the following is not a medium for sound waves?
solid |
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liquid |
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vacuum |
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none of these is a medium for sound waves |
A vibrating object produces a sound wave that travels outwardly from the object through a medium (any liquid or solid matter). The vibration disturbs the particles in the surrounding medium, those particles disturb the particules next to them, and so on, as the sound propagates away from the vibration.
In the metric system, what prefix represents 103?
centi |
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milli |
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mega |
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kilo |
Kilo is the metric system prefix for 103.