Question

q4. a piece of foam is pushed underwater but pops back up. why? a. it is denser than water b. it is less dense than water c. it has the same density as water d. it has no mass

Explanation:

To determine why the foam pops back up, we use the principle of buoyancy. An object floats (or pops up) in a fluid when its density is less than the fluid's density. Water has a certain density, and if the foam is less dense than water, the buoyant force (upward force from water) is greater than the foam's weight, causing it to rise. Option A is incorrect because a denser object would sink. Option C is incorrect as equal density would mean neutral buoyancy (not popping up). Option D is incorrect because all matter has mass. So the foam pops up because it is less dense than water.

Answer:

B. It is less dense than water