Buoyant Force

  1. A completely submerged body displaces a volume of liquid equal to its own volume. The buoyant force equals the weight of the fluid displaced.
  2. When an object weights less than the total volume of fluid it can displace, it will settle down until the buoyant force equals the weight and it floats partially submerged.

This java applet shows effect of buoyant force acting on an object (less dense than water).

  1. You can change the density of the floating object (square block)
  2. click the mouse near the top of the gray area within top left block.
    drag the mouse up and down to change the density.
  3. Another block on the right has the same amount of gray area
    1. this gray area will be redistributed uniformly.
    2. (Same mass distributed over larger volume --
    3. the block starts moving down until the buoyant force equals its weight .
    4. the volume displaced is represented by the gray area at the lower left corner.
    5. the curve for pressure varies with depth is shown on the right side.
  4. When the block is in equilibrium,
  5. you can click within the block and drag it up and down.
    the difference between the gravitation force and the buoyant force cause the block to move sinusoidally. (SHM)
  6. During the animation:
  7. press the mouse button to suspend the animation. (release the mouse button to resume)

Your suggestions are highly appreciated! Please click hwang@phy03.phy.ntnu.edu.tw

AuthorĄGFu-Kwun Hwang, Dept. of physics, National Taiwan Normal University

Last modifiedĄG