Answer:
a = 0
Explanation:
The velocity of a sound wave in a straight line is 660 mph. The wave is moving with a constant velocity. It means that the change in velocity is equal to 0.
We know that acceleration of an object is equal to the change in velocity divided by time taken. But here the change in velocity is 0. As a result the acceleration of the sound wave is 0.
Each magnet has a north pole and a south pole. We know that, from having played with bar magnets in our childhood, that a magnet's north pole will repel another magnet's north pole and attract its south pole.
From this diagram it is easy to see that the two lower bar magnets not only repel each other, but they are quite attracted to each other since their north and south poles are close together.
Therefore the region between the lower two magnets has the least force of repulsion.
The molecules of ice stick together in the process of cohesion. They are tightly packed so there isn't much room to move. Liquid water is a looser hold. The molecules can go past one another, and they will take the shape of whatever container they occupy. Water vapor is loosely contained, and it will will fill whatever container it is kept in, and it will take its shape, too.
1 cubic cm is the same as 1 mL, so the answer would be C.