1. The problem statement, all variables and given/known data This is a concept question rather than a homework question, so i don't have any value for the question. From the figures below, the object is turning horizontally. how do we know the object will start sliding up or sliding down at what angular velocity if there is no angular acceleration. Let's assume there is a friction force along the sliding path. http://img199.imageshack.us/img199/8453/p667.gif [Broken]http://img21.imageshack.us/img21/520/slideupordown.jpg [Broken] 3. The attempt at a solution 1. What kind of friction coefficient should we use, static friction or kinetic friction? 2. i've draw out the free body, but still can't figure out the way to know the object will start to move at what angular speed? but i believe the free body diagram of both situations are the same. http://img29.imageshack.us/img29/4503/slidedown.jpg [Broken] by using sum of Falong the sliding path = m(accos [tex]\vartheta[/tex])?