1. The problem statement, all variables and given/known data There is a ball spinning on a string in a circle in a horizontal plane in a gravitational field. What is the rotational frequency w in terms of the angle of the string to the normal line of the plane of motion, the length of the string, m, and g? The original homework was actually something much more complicated with 3 masses and I was supposed to use Lagrangian mechanics to solve, but I got a very strange answer that I did not like, so I tried doing a simpler problem using physics 101, but my answer is the same as what I calculated with the lagrangian if you set the other two masses to 0. Please look at this it is very strange. 2. Relevant equations You can solve this using basic physics 3. The attempt at a solution Obviously if the system is in equilibrium then the mass is moving neither up nor down, so mg = Tcos(theta), where mg is gravity, T is tension, and theta is the angle between the string and a line that goes straight up and down. Also we have mV^2/r = ma = Tsin(theta). r must be Lsin(theta) and v is rw. Substituting for T and flipping everything around gives you sqrt(g/L/cos(theta)) = w. This is a very, very strange answer. It is not possible to make w = to 0 with any theta with this equation. This means that if you have a point mass hanging from a string in a gravitational field that it spins around for no god damn reason. Since L is on the bottom of the fraction, it would seem to indicate that a point mass merely existing in a gravitational field rotates infinitely quickly. The steps are very simple and I've checked them several times. Can someone either explain to me what I did wrong or why a mass hanging from a string always spins in place? If you write it in terms of V instead of w then you get V = sqrt((gL)tan(theta)sin(theta)) = V, which looks more reasonable because V = 0 for theta = 0 and V = infinity for theta = 90 degrees.