1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Rotating Pail of Water

  1. Nov 3, 2007 #1
    1. The problem statement, all variables and given/known data
    A rotating pail of water with an angular velocity w has a surface curving up from the centre to the outer edge. Find the shape of the surface. The slope of the surface is dy/dx = tan(theta) at position x is y (= function of x) is the shape of the surface. You must resolve forces to find tan(theta) as a function of x, and then solve for the height, y, as a function of x.

    If the pail rotates once per second, and has a diameter of 0.45 m, how high above the centre is the outer edge?

    2. Relevant equations

    3. The attempt at a solution
    All I see is that w = 2pi rad/sec and r = 0.225 m.
  2. jcsd
  3. Nov 4, 2007 #2
    Method I:
    Ideal Fluid, by definition, can not tolerate any shear force. Use this fact.
    Assume the centre of the water surface to be origin. Let P(x,y) be a point on the water surface. Consider forces on it. Impose the condition that tangential force will be zero.
    I hope you can proceed now.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook