Question

Suppose you had two cubes that had masses of exactly 1 kilogram. You placed both in a large swimming pool. One cube sank and came to rest on the bottom of the pool. And, the other cube floated at rest while only partially submerged. Which cube (if either) has a larger buoyant force acting on it? Explain how you know.

Answer 1

The cube that is floating that has larger buoyant force acting on it.
Net force on the cube = Downward gravitational force - Upward buoyant force
F = mg - Fb
Downward gravitational force is same for both the cubes since their masses are equal. The gravitational force in the cube that sank is greater and the buoyant force in not enough to make it float. This may be because the density of the floating cube may be less and it displaced more water than the cube that sank.