Back to 11.2 Density

11.2 Exercise 3

Avg difficulty 2.5

A cube of polystyrene measuring 10 cm per side lies partially submerged in a large container of water.

  1. If 90% of the polystyrene floats above the surface of the water, what is the density of the polystyrene? (Note: The density of water is 1000 kg/m3.)
  2. A 0.5 kg mass is placed on the block of polystyrene. What percentage of the block now remains above water?
  3. The water is poured out of the container and replaced with ethyl alcohol (density = 790 kg/m3).
    1. Will the block be able to remain partially submerged in this new fluid? Explain.
    2. Will the block be able to remain partially submerged in this new fluid with the 0.5 kg mass placed on top? Explain.
  4. Without using a container of water, explain how you could determine the density of the polystyrene mentioned above if the material instead were spherical.

OpenStax College Physics 2e, 11.2 Density, exercise 3

AI Tutor

Adapted from College Physics © 2022 Rice University. Licensed under CC BY 4.0. Sources: College Physics 2e, College Physics for AP® Courses 2e. Imported at revision f98d7a7.