The buoyant force increases as you push an inflated beach ball under the water's surface. When will the force stop increasing? Explain your reasoning.

The force will stop to increase when the ball is fully immersed into water.

Explanation:

According to Archimedes's principle:

"The force of buoyancy that is exerted by a fluid on an object equals the weight of the fluid displaced by the object."

When we push a inflated ball into water since the volume of the water that the beach ball displaces as the ball goes on into the water goes on increasing thus according to the buoyancy principle the force on the ball should also increase proportionally. But when the ball is fully immersed into water since it cannot displace any additional water thus the force of buoyancy achieves a constant value and hence stops to increase.