Clarify what you mean by ratios?
Answer:
The last one makes the most sense as they combine two like things that are easy to visualize
Explanation:
-- The speed of light in air is very close to 3 x 10⁸ m/s.
Whatever the actual number is, it's equivalent to roughly
7 times around the Earth in 1 second. So for this kind of
problem, you can assume that we see things at the same time
that they happen; don't bother worrying about how long it takes
for the light to reach you.
-- For sound, it's a different story. Sound in air only travels at
about 340 m/s. It takes sound almost 5 seconds to go 1 mile.
-- Now, the lightning and thunder happen at the same time.
The light travels to you at the speed of light, so you see the
lightning pretty much when it happens. But the sound of the
thunder comes poking along at 340 m/s, and arrives AFTER
the sight of the lightning.
The length of time between the sight and the sound is about
99.9999% the result of the time it takes the sound to reach you.
If the thunder arrived at you 3 seconds after the light did, then
the sound traveled
(340 m/s) x (3 s) = 1,020 meters .
(about 0.63 of a mile)
(If you're worried about ignoring the time it takes
for the light to reach you ...
It takes light 0.0000034 second to cover the same 1,020 meters,
so including it in the calculation would not change the answer.)
The equation of our ellipse is:
(1)
First, let's reduce the equation of the ellipse to the standard form:

To do that, we should divide both terms of equation (1) by 6400, and we get:

This is a vertical ellipse (because
) centered in the origin, and so the distance of its foci from the origin (on the y axis) is given by

Therefore, the position of the two foci is (0,6) and (0,-6)
Answer:
That is a very broad question. One thing that does not seem to be considered is the depletion of the ozone layer at high altitudes.
In the 1960's chlorofluorcarbons (CFC,s) became popular as refrigerants, spray can propellants, etc. In January 1989 the Montreal Protocol was passed which has greatly reduced the use of these substances. However, it may be several decades before the ozone layer can be replaced and again absorb harmful ulraviolet rays that may be partly responsible for the increase in global warming.
(One chlorine atom at high altitudes can be responsible for the destruction of 100,000 molecules of ozone - catalytic reaction)