4. Two students walk in the same direction along a straight path, at a constant speed -- one at 9 m/s and the other at 1.9 m/s
2. Assuming that they start at the same point and the same time, how much sooner does the faster
student arrive at a destination 780 m away?
b. If student I increases his speed to 1.2 m/s, how much sooner does the faster student arrive at the same
destination?

50 inches should be the resultant vector

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.

that tool is called an altimeter which measures your altitude which can be used to tell which atmosphere you are currently in, including the stratosphere.

hope this ! : )