1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

A SHM problem of floating

  1. Feb 15, 2007 #1
    1. The problem statement, all variables and given/known data
    There is a ship of mass M floating on a river. The upper portion of the ship has a uniform cross-sectional area A and the density of water is d. Now the ship is displaced a further depth y into the water and released.
    What is the resultant force acting on the ship when it is displaced a further depth y into the water?

    3. The attempt at a solution
    d = m / v where m is the mass of water and v is volume of water being pushed by ship
    m = d (A*y)
    net F= Mg - mg
    net F= g [ M - d (A*y) ]

    The correct answer is F= - dgAy. Why isn't the weight of the ship taken into account?
    Thank you so much!
  2. jcsd
  3. Feb 15, 2007 #2


    User Avatar
    Science Advisor
    Homework Helper

    The ship is floating on the river. So the buoyancy force for the part of the ship that was below the waterline when y = 0 equals its weight Mg.
  4. Feb 15, 2007 #3
    Initially, [tex]F_b=dAy_o[/tex] where [tex]y_o[/tex] is the intial depth of the ship. The depth of the ship when its pushed down by a length dy (or y) is [tex]y_o+dy (or y_o+y)[/tex]
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: A SHM problem of floating
  1. SHM problem (Replies: 2)

  2. SHM Problem (Replies: 8)

  3. A SHM problem! (Replies: 7)

  4. A SHM problem (Replies: 4)

  5. SHM Problem (Replies: 1)