1. The problem statement, all variables and given/known data So i have to do a lab about circular motion we had to swing a rubber stopper around while holding a glass tube and when there was a mass hanging at the end of it "plot a graph so the slope of the straight line graph may be used to determine the mass of the stopper" we changed the mass at the bottom and varied the length of the string, but i don't know if this is a problem or not we were going to plot a centripetal force as a function of centripetal acceleration graph, and find the slope to find the mass of the stopper we measured time (t) in seconds, the length of the string (r) in meters, the mass hanging mass (m1) in kilograms, and we were supposed to calculate centripetal acceleration (ac) in meters per second squared, centripetal force, (Fc) in newtons, and velocity (v) in meters per second, and we had to find the mass of the stopper (m2) in kilograms, but we measured it for percent error (this is one of the trials m1 = .05 kg, t =.486 s, r =.295 m, Fc = .49N, ac = ?, v = ? m2 = ? 2. Relevant equations Fc=m1g Fc=m2ac = m2v2/r C=2∏r v= C/t 3. The attempt at a solution So, i tried to find the velocity and the acceleration and they just did not make any sense at all, so i'm wondering if anyone can help me figure out what i did wrong. C=2∏r C=(2)(∏)(.295m) C=1.854m v=C/t v=1.854m/.45s v=4.12m/s ac=v2/r ac[/SUP]=(4.12m/s)2/.295m ac=57.5m/s2 which does not make any physical sense at all, HELP.