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!

Boyancy Problem

  1. Apr 7, 2005 #1
    What in am doing wrong? I assumed it's just the volume of the tank and then you find the weight of the water displaced. It's not working. I made sure that the diameter was changed into a radius for the volume of the sphere. Also as a sanity note, if you have a tank that sinks when it's empty it should still sink if it's full of air right?
     
    Last edited: Apr 7, 2005
  2. jcsd
  3. Apr 7, 2005 #2

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    It's really simple.
    a)[itex] F_ {APXIMN\Delta N\Sigma} = V_{sphere}\rho_{water} g [/tex]

    That's the scalar.

    For point b),apply Newton's second law for the sphere.How many forces act on the batiscaph?

    Daniel.
     
  4. Apr 7, 2005 #3
    Yeah which is why I hate it when I get these problems wrong.:) I know that has to be the answer. I can't figure out why Im not getting the right number. Here is what I am getting. 1108353.888 Newtons.
     
  5. Apr 7, 2005 #4
    Dex why are you writing hieroglyphs for very simple formulas :bugeye: .

    Adam, [tex]F_B = \frac{4}{3}\pi r^3\rho_{w}g = F_B = \frac{4}{3}\pi (6m)^3(1000kg/m^3)(9.8m/s^2) = 8.87 * 10^6 N[/tex].
    Right?
     
  6. Apr 7, 2005 #5
    Yeah. Your equation is right. Though don't you need to divide the diamter by two to get the radius? I checked neither of those two possible solutions are correct.
     
    Last edited: Apr 7, 2005
  7. Apr 7, 2005 #6
    The problem I did like this used

    [tex]
    \begin{multline*}
    \Sigma F_{y}=F_{b}-F_{t}-F_{g}\\F_{g}=ma
    \end{multline*}
    [/tex]

    with gravity and tension in the negative y direction.
     
    Last edited: Apr 7, 2005
  8. Apr 7, 2005 #7

    dextercioby

    User Avatar
    Science Advisor
    Homework Helper

    Ramollari,the radius is 3m...:wink:

    Hey,hieroglyphs are from ancient Egypt.Those were capital Greek letters...Hey,you are Greek!! :rofl:

    Daniel.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Boyancy Problem
  1. Air Boyancy Question (Replies: 4)

  2. Boyancy project help (Replies: 4)

  3. Basic Boyancy problem (Replies: 4)

  4. Density and Boyancy (Replies: 1)

Loading...