Every single answer to all of these questions is in the part of
your textbook or online course right before this problem.
12). The person transfers ENERGY to the rope.
Then, the wave carries the ENERGY along the rope to the door.
13). Arrow-B is pointing in the direction the ENERGY travels,
as the wave moves from the person's hand to the door.
14). The rope is the "medium" that the wave travels through.
Every point on the rope moves up and down, all at different times.
They DON't move forward or backward, only up and down ... across
the direction the wave is moving.
15). This is called a TRANSVERSE wave, because the particles
of the medium move ACROSS the direction the wave is moving.
The wave is moving from the person's hand to the door, but the
particles of the medium move up and down.
"Transverse' means "across".
16). Point-C is called a TROUGH of the wave. It's the lowest part of
the wave, and it's pronounced like "TRAWF", rhymes with "cough".
A trough is also the long basin where the farmer pours water for the
horses or cows to drink from.
Look at ' C ' in the picture. The trough of the wave is shaped
just like the drinking trough.