Answer and Explanation:
The formation of planets ,initially was the result of gradual accumulation of solid matter into the solar nebula. As a result of high temperature in the interior of our solar system, metals and rocks were the only materials to get compressed.
The matter that was volatile could not be compressed so close to the heat energy radiated by the early Sun.
On the outer part of the solar system, solid matter included hydrogen compounds, rocks and metals with a lot of matter for planet formation.
The Giant planets were formed by capturing Helium and hydrogen gases as well whereas the terrestrial planets being much more smaller are made up of mainly rocks like silicates and metals like iron.
The moons of terrestrial planets like that of Earth is also terrestrial in nature consisting of rocks and metals as the constituent material while that of giant planets consist of frozen water in half the proportion and the other half is rocks and metals.
I believe it is Acoustics, the real name for it would be like Reverberation. But go with Acoustics. :)
Let car A's starting position be the origin, so that its position at time <em>t</em> is
A: <em>x</em> = (40 m/s) <em>t</em>
and car B has position at time <em>t</em> of
B: <em>x</em> = 100 m - (60 m/s) <em>t</em>
<em />
They meet when their positions are equal:
(40 m/s) <em>t</em> = 100 m - (60 m/s) <em>t</em>
(100 m/s) <em>t</em> = 100 m
<em>t</em> = (100 m) / (100 m/s) = 1 s
so the cars meet 1 second after they start moving.
They are 100 m apart when the difference in their positions is equal to 100 m:
(40 m/s) <em>t</em> - (100 m - (60 m/s) <em>t</em>) = 100 m
(subtract car B's position from car A's position because we take car A's direction to be positive)
(100 m/s) <em>t</em> = 200 m
<em>t</em> = (200 m) / (100 m/s) = 2 s
so the cars are 100 m apart after 2 seconds.
