As a rock sinks deeper and deeper into water of constant density, what happens to the buoyant force on it if it started above the surface of the water?
A) The buoyant force remains constant.
B) The buoyant force steadily decreases.
C) The buoyant force first increases and then remains constant.
D) The buoyant force keeps increasing steadily.

Question

Quizplus · Accepted Answer

The buoyant force is equal to the weight of the water displaced by the rock. As the rock sinks deeper into the water, it displaces more water, so the buoyant force increases. However, once the rock is completely submerged, the amount of water it displaces remains constant, so the buoyant force also remains constant.

As a Rock Sinks Deeper and Deeper into Water of Constant