Which of the following best describes the formation of surf? Waves energy, rebounding from its impact with shore, crashes into oncoming waves, causing them to break. Entering shallow water forces wave energy upward, making the wave crest unstable and causing it to break. A wave encountering shallow water begins to slow at its bottom, while the top of the wave continues at its previous speed. This causes the wave to break. As waves enter shallow water, the distance between wave crests (wave length) shortens, increasing the tendency to break.

The question above would be written again but this time with options attached to it for comprehension sake:

Which of the following best describes the formation of surf?

A.  Waves energy, rebounding from its impact with shore, crashes into oncoming waves, causing them to break.

B. Entering shallow water forces wave energy upward, making the wave crest unstable and causing it to break.

C. A wave encountering shallow water begins to slow at its bottom, while the top of the wave continues at its previous speed. This causes the wave to break.

D. As waves enter shallow water, the distance between wave crests (wavelength) shortens, increasing the tendency to break.

The correct answer is option C (A wave encountering shallow water begins to slow at its bottom, while the top of the wave continues at its previous speed. This causes the wave to break).

Explanation:

Surf could mean crashing waves or breaking waves. Generally, the wave speed is constant in the same medium, however, the wave speed decreases as it enters shallow water which is largely due to the water depth which is relatively small, especially when it encounters the bottom of the shallow water. While the top of the wave overtakes the bottom of the wave, making sure the top of the wave continues at its previous speed.

not too sure thinking all accelerations are pointed down