Two main factors affect the speed of sound: the material that makes up the medium—such as air or water—and the temperature. If we know the medium and the temperature, however, we can predict the speed of sound.
Answer:
True.
Below answers 7 - 8 - 9
Explanation:
7 - With the advent of spacecraft and radar, more precise methods emerged for making a direct measure of the distance between the Earth and the sun. The definition of AU had been "the radius of an unperturbed circular Newtonian orbit about the sun of a particle having infinitesimal mass, moving with a mean motion of 0.01720209895 radians per day (known as the Gaussian constant)" We can say that one astronomical unit (AU) represents the mean distance between the Earth and our sun. An AU is approximately 93 million miles (150 million km)
. It's approximately 8 light-minutes.
8 - One of the main scientific justifications for building Hubble was to measure the size and age of the Universe and test theories about its origin. Images of faint galaxies give 'fossil' clues as to how the Universe looked in the remote past and how it may have evolved with time. The Deep Fields gave astronomers the first really clear look back to the time when galaxies were forming.
The Hubble Ultra Deep Field from 2004 represents the deepest portrait of the visible universe ever achieved by humankind. The Ultra Deep Fields show the furthest away galaxies that can be observed in visible light.
9 - It’s true that the moon goes around Earth every month, but it doesn’t always get in Earth’s shadow. The moon’s path around Earth is tilted compared to Earth’s orbit around the sun. The moon can be behind Earth but still get hit by light from the sun.
Answer:
C. replacing with minerals creates petrified fossils
Explanation:
most likely answer
All of Earth
<span>only areas near the North Pole and South Pole </span>
<span>much of Earth, including parts that are much warmer today </span>
<span>only oceans, not land</span>
The speed of a river varies from close to 0 m/s to 3.1 m/s (7 mph). Factors that affect the speed of a river include the slope gradient, the roughness of the channel, and tides. Rivers tend to flow from a higher elevation to a lower elevation.
