C dependent variable because dependent means relying on something else
C because of the positioning of the initial ray of refraction
An ice cube causes hot coffee to become cool because the amount of coldness contrasts the hot coffee to make it a little cooler
If you heat that air by 100 degrees F, it weighs about 7 grams less. Therefore, each cubic foot of air contained in a hot air balloon can lift about 7 grams. That's not much, and this is why hot air balloons are so huge -- to lift 1,000 pounds, you need about 65,000 cubic feet of hot air.
