The most important question to answer here is what happens when an object undergoing Uniform Horizontal Circular Motion(tethered to a string, NOT using gravity as sole centripital acceleration) will behave when it reaches that perfect right angle to gravity. I would like to insert a drawing but I'm hoping my words can explain just as well. Assume this: There is a 1 kg mass on the end of a 1 m string that is being ACCELERATED in a uniform circle. As the velocity increases, the centripital acceleration increases, therefore tension increases. Now, while the string is at an acute angle with its vertical center there is both a horizontal and vertical component to its tension. As these components increase and the angle nears 90 degrees... what happens? After thought I have theorized that the object will fluctuate around the horizontal axis because as the vertical component equals gravity the object and string are brought up to a perfect horizontal and then, because there is no vertical component, the weight starts to go back down. I know it is not the most complex thing to spend time figuring out, but I'm only starting to get into physics and I want to mke sure I am on firm ground before studying anything more fascinating than a rotating object (which I, myself, find rather fascinating anyways).