Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Ball falling of a hemisphere

  1. Jul 21, 2011 #1
    1. The problem statement, all variables and given/known data
    A ball with initial velocity 0 and mass m starts at the top of a hemisphere and begins to slid down the frictionless side. The radius of the hemisphere is r. At what angle does the ball fall off the hemisphere?

    2. Relevant equations
    mgsintheta, mgcostheta, fn

    3. The attempt at a solution
    I guess that you can split mg into mgsin theta and mg cos theta and that one of them would create centripetal force. Then you can find where the centripetal force is 0 because there would be no normal force when the ball falls off? I'm not sure. Also, my teacher mentioned that there is a way to solve this with and without calculus.
  2. jcsd
  3. Jul 21, 2011 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    Find the place (or time) at which the normal force becomes zero, if you constrain the ball is constrained to remain on the surface of the hemisphere.
  4. Jul 22, 2011 #3
    you can use energy to find theta, solve v then substitute into your force equation
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook