1. The problem statement, all variables and given/known data The half a sphere with a 'm' mass and 'r' radius is equilibrated on a plan absolutely polished horizontal with the side of the AB wire. So the surface of the half a sphere has with the horizontal plan an alpha angle. Find, after the break of the wire, the velocity of the O center and her maximal value too, also the maximal value of the pressure of the half-sphere over the horizontal. Find that for small angles it behaves like a mathematical pendulum. Illustration: http://img135.imageshack.us/img135/9526/fiz1rf6.th.jpg [Broken] 2. Relevant equations 3. The attempt at a solution I think that the lagrange's equations can be employed to solve it.