Dynamics Problem: Spinning cone with mass!?

Question

The sides of a cone make an angle "THETA" with the vertical. A small mass "m" is placed on the inside of the cone and the cone, with its point down, is revolved at a frequency "f" about its symmetry axis. If the coefficient of static friction is "MU", at what positions on the cone can the mass be placed without sliding on the code? (Give the maximum and minimum distances, "r", from the axis)


I guess what it boils down to is what forces are acting on the mass... what am I missing. So far I have these forces:
Centripetal, friction, and gravity. Is that it? And is (f/(2*pi*r)) equal to velocity?

Answer 1

v=2 pi f r and F=mv^2 / r
find normal force perpendicular to surface of cone as a function of r by finding the components of the gravitational and centripetal force normal to the surface. Then calculate the frictional force and set it equal to the components of the gravitational and centripetal force parallel to the surface. Solve for r, you should get 2 values.

Answer 2

enable's say for the sake of argument that a deity is in the back of all of it. What reason might everybody could think of you or the different human theist have a obscure theory what that entity is, no longer to show that it incredibly is a Bronze Age Canaanite mountain god that demands animal sacrifice, friends with human beings and dictates books of political and non secular commentaries packed with inner contradictions and errors that a 5th grader could spot if no longer brainwashed to rationalize them away ? Oh, and what keeps your God spinning? Why does each and everything else desire reason yet he does not, different than you like it that way? If he can spin without reason then why won't be in a position to the universe be causeless? it is called an "pointless middleman" an theory from good judgment, so of direction you as a theist might have under no circumstances heard of it. And BTW, is each and everything you don't comprehend the magic of a Canaanite mountain god? this is extremely what theists do, isn't it? "i'm no longer clever sufficient to determine it out, so it is going to be magic!" there is a lot that i'm no longer clever sufficient to come to a decision, yet i'm clever sufficient to comprehend maximum all the failings attributed to magic and demons in the previous have became out to be neither, like Biblical descriptions of epilepsy being attributed to demon posession.