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.
<span>Some geographic areas endure cycles between these two processes called transgressive-regressive sequences. The rocks of western Pennsylvania are one example. Sandy beaches often leave observable records of transgression by covering marsh sediments that were once behind it as it moves inland. The original sediments are then covered by even deeper water sediments, which geologists can trace and record. It is generally believed that transgression will increase in accordance with rising sea levels worldwide</span>
Plant trees around the perimeter of his fields
