Answer:
To summarize, <em><u>Jane's star</u></em> has a <em><u>red</u></em> light and <em><u>is traveling towards</u></em> the <em><u>Earth</u></em> while <em><u>John's star </u></em>has a <em><u>blue</u></em> light and <em><u>is traveling away</u></em> from the <em><u>Earth</u></em>. This is a <em><u>prime example</u></em> of the <em><u>Doppler Effect</u></em> in <em><u>motion</u></em>. The stars <em><u>look different </u></em>because <em><u>they are traveling in different directions.</u></em>
The way I look at these things is like this:
-- The runner covered 12 meters in 4 seconds.
Average speed = 3 meters per second.
-- Speed at the beginning = zero.
In order to make the average 3, Speed at the end = 6 meters per second.
-- Speed increased from zero to 6 meters per second in 4 seconds.
It must have increased 1.5 meters per second each second.
That's choice-#2.
dry ice is one example of this.
