I have a problem here that looks simple to me, but has been driving me crazy: Basically, it's an object weighing 3.33N at the end of a string of unknown length, which is in turn attached to a spring scale. The object is being spun in a circle with a radius of 1.49m. The person spinning the object is trying to spin the object with a velocity that will have the spring scale showing a weight of 4.44N (as opposed to the actual weight of 3.33N). I need to determing the necessary velocity, the angle the object swings from vertical, the force the object exerts on the string, and the force necessary to keep the object moving on the circular path. I tried using the equation Fc = mv^2/r, which I algebraically rearranged to solve for v, but I'm not sure if that's correct. If I put 4.44N in for Fc and solve for v, I get 4.4m/s, which doesn't seem right. From there, I'm totally lost. If I could at least get the first two parts (v and angle), I'd probably be ok. I drew a free-body diagram to help me visualize the angle and figure it can be determine trigonometrically, but I don't think I have enough info to use sin and cos. Any help you could give me to guide me on this would be appreciated.