Question

Density of fresh water is less than that of salt water. Block A and Block B are exactly the same. Block A floats quietly in fresh water with part of its volume above the water surface, and Block B floats quietly in salt water with part of its volume above the water surface. Which of the following statements comparing the buoyant forces on the two blocks is true?

Answer 1

The buoyant force is equal to the weight of the displaced fluid. Since salt water is denser than fresh water, Block B in salt water displaces a greater weight of water than Block A in fresh water, and thus experiences a greater buoyant force.

Step-by-step explanation:

The question regarding buoyant forces on two identical blocks floating in different liquids directly relates to the principles of physics, specifically fluid dynamics. To compare the buoyant forces on Block A in fresh water and Block B in salt water, we must understand that the buoyant force is equal to the weight of the fluid displaced by the object. Since salt water has a greater density than fresh water, less salt water needs to be displaced for an object to float. Therefore, if Blocks A and B are identical and both float with part of their volume above the water surface, the amount of water displaced by both blocks is the same, which means the weight of the water displaced, and hence the buoyant force, is greater for Block B in salt water because salt water is denser.