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Re-Post of a Bouyancy Problem

  1. Feb 4, 2007 #1
    Previous Thread

    Problem, again.. The bottom of a steel "boat" is a 7.00 m\times 9.00 m\times 5.00 cm piece of steel (Psteel=7900). The sides are made of 0.540 cm-thick steel.
    What minimum height must the sides have for this boat to float in perfectly calm water?

    Question- How the heck did the person in previous post get that big long equation?

    My books says the hmin=Mass/Pf*A.

    Im having trouble differing the Mass. I tried to find it from the equation Pavg=M/AH. 7900=x/5*10*.02...

    Appreciate your help, this chapter is killing me.
  2. jcsd
  3. Feb 4, 2007 #2
    The boat displaces a weight of water equal to its own weight.

    The left side of that equation is equal to the weight of the boat.

    Weight of bottom + [total volume of the sides(2h(L+W))][density of the steel][g]

    The right side is the weight of the water displaced by the boat, which is the volume of the boat times the density of water, times g.
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