The top surface of a calm, smoothly flowing stream is always at atmospheric pressure. As water in this stream runs into a tree stump and slows almost to a stop, the water's top surface
A) shifts upward slightly above the normal stream level.
B) shifts downward slightly below the normal stream level.
C) stays at the same height and does not begin to rotate.
D) stays at the same height but begins to rotate clockwise as viewed from above.

Question

Quizplus · Accepted Answer

When water slows down, such as when it encounters an obstacle like a tree stump, the kinetic energy of the water is converted into potential energy, causing the water level to rise slightly. This is in accordance with the principle of conservation of energy.

The Top Surface of a Calm, Smoothly Flowing Stream Is