Answer:
I think sound does not travel at all in space. The vacuum of outer space has essentially zero air. Because sound is just vibrating air, space has no air to vibrate and therefore no sound. If you are sitting in a space ship and another space ship explodes, you would hear nothing.
Explanation:
Wavelength = speed / frequency = 340 / 17000 = 0.02 m
Explanation:
The runner was 8.6km away from the finish line when the bird starts flying.
Therefore it takes the bird 8.6/14.4 = 0.60 hours for the bird to fly to the finish line.
In that 0.60 hours, the runner would have ran an extra 3.6km/h * 0.6h = 2.16km.
Now, the runner and the bird are flying towards each other. The distance between them is 8.6 - 2.16 = 6.44km and their combined speed is 18.0km.
Hence, they will meet in 6.44/18.0 = 0.36 hours.
Overall, the bird flew for 0.60 + 0.36 = 0.96 hours, and flew 14.4km/h * 0.96h = 13.8km.
C. Usually when an atom loses or gains an electron, it is because it is trying to satisfy the Octet Rule. The Octet Rule states that an atom is at its stablest when it has 8 valence electrons (two in helium's case)
If you look on the periodic table, elements on the left (Alkaline Metals) are the most reactive because they only have one valence electron (or electron in the outer shell). Elements on the right (Noble Gases) are the least reactive because they have a full outer shell of 8 valence electrons.
Later on you will find that as stability decreases as you go down the periodic table but that is a discussion for a different time.
Hello
This is a problem of accelerated motion, where the acceleration involved is the gravitational acceleration:

, and where the negative sign means it points downwards, against the direction of the motion.
Therefore, we can use the following formula to solve the problem:

where

is the initial vertical velocity of the athlete,

is the vertical velocity of the athlete at the maximum height (and

at maximum height of an accelerated motion) and S is the distance covered between the initial and final moment (i.e., it is the maximum height). Re-arranging the equation, we get