An acorn falls from rest from the top of a 21 m tall oak tree. a. how long does it take for the acorn to fall to the ground? b. how fast is the acorn going before it hits the ground?

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.

cancer risk hope this

float.

archimedes' principle

denser than water sinks in water.

denser than mercury would sink in it

0.93xc=0.93x3x10^8m/s

2.54cm is 1 inch

360seconds i 1 hr