I'm doing an experiment that requires me to balance a ring, tied to four strings, in the middle of a force table; in other words, the objective is to set the ring at equilibrium. Each string is mounted on a pulley, with different mass hanging off of them. Tension and friction are really the only forces acting on this set up.
I've reached the configuration where the ring is very reasonably in equilibrium, but it's just slightly "out of focus". But I've also noticed that sometimes, when the ring is very noticeably not in equilibrium, ie. it's wildly far away from the center of the force table, the ring will still remain stationary, as if it's at equilibrium.
My personal guesses is that it has something to do with static friction (I'm not familiar with static friction, this is just a blind stab at it) or each strings also exerting some horizontal force in the groove of their pulleys, in addition to vertical tension they're pulling the ring from the hanging mass. Or maybe the x/y components cancels out, and the remaining components is not enough to overcome friction to continue pulling the ring, or it's just to small altogether to do anything.
I'm also thinking that since my configuration is just slightly out of center, whatever is making the way out of center configuration stationary also affects my configuration, but to a much smaller and negligible degree.