Answer:
Positive velocity and negative acceleration
Explanation:
An object moving in the positive direction has a positive velocity.
An object that's slowing down while moving in the positive direction has a negative acceleration.
Answer:
The average speed of the elevator going down in the abandoned mine is 17.722mph.
Explanation:
If the elevator takes 90 seconds to descend a height of 713m, the average speed of the elevator is:

And if 1m/s is 2.23694mph, the average speed is:
.
Number 4 is c , number 5 is a , number 6 is d and 7 is a
Before Copernicus most people were thinking that the Earth is at center of universe. In 1609 Galileo observed sky through his home made telescope.
He found 4 moons orbiting Jupiter..It was a proof that bodies are orbiting other planets and not earth alone. <span>He found the crescent shape of Venus through his telescope and this could happen only if Sun is at center.</span>
The answer is A because it is an example of red shift which if basically the Doppler effect , but for light. The wavelength gets longer because it has visible light has shifted into the red end of the spectrum, showing that it has a shorter frequency with a longer wavelength; meaning it is moving away from us