| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.05 |
| Score | 0% | 61% |
Which of Earth's layers has weather?
mesosphere |
|
troposphere |
|
stratosphere |
|
thermosphere |
The Earth's atmosphere has several layers starting with the troposphere which is closest in proximity to the surface. Containing most of the Earth's breathable air (oxygen and nitrogen), it's a region with warmer temperatures closer to the surface and cooler temperatures farther away which results in the rising and falling air that generates weather.
Which of the following is not a characteristic of the Sun?
is a yellow dwarf star |
|
makes up over 99% of the mass of the solar system |
|
is composed of hydrogen and helium |
|
formed 2.6 billion years ago |
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.
Molecules and atoms that are inputs to a chemical reaction are known as which of the following?
reactants |
|
components |
|
products |
|
fuel |
During a chemical reaction molecules and atoms (reactants) are rearranged into new combinations that result in new kinds of atoms or molecules (products).
Acceleration is the rate of change of velocity per unit of time. Which of these is the formula for acceleration?
\(\vec{a} = { \vec{v} \over t }\) |
|
\(\vec{a} = { t \over \Delta \vec{v} }\) |
|
\(\vec{a} = { \Delta \vec{v} \over t }\) |
|
\(\vec{a} = \Delta \vec{v} t \) |
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 \(\vec{a} = { \Delta \vec{v} \over t }\)
The Earth's rocks fall into three categories based on how they're formed. Which of the following is formed when existing rock is altered through pressure, temperature, or chemical processes?
igneous |
|
metamorphic |
|
coal |
|
sedimentary |
The Earth's rocks fall into three categories based on how they're formed. Igneous rock (granite, basalt, obsidian) is formed from the hardening of molten rock (lava), sedimentary rock (shale, sandstone, coal) is formed by the gradual despositing and cementing of rock and other debris, and metamorphic rock (marble, slate, quartzite) which is formed when existing rock is altered though pressure, temperature, or chemical processes.