1. The problem statement, all variables and given/known data Since I ran out of time in class, I have to make up my own times for this lab using calculations. The lab consists of our providing a little force by shaking this tube. Inside this tube is a string, and at one end of the string is attached a hanging mass, the other end a rubber stopper. Essentially, the hanging mass's weight is what provides the centripetal force of the rubber stopper. However, my calculations for the time in seconds are waaay too high. I tried doing the same method for my other trials done in class and they were also far too high. I don't know what I'm doing wrong, because human error couldn't have possibly been that high all 10 trials in class. m1 = 0.011 kg m2 = 0.030 kg r = 0.545 m g = 9.81 m/s2 2. Relevant equations d = r * 2 pi * 20 (we measured the time it took for 20 revolutions) t = d / v W = mg Fc = (mv2) / r 3. The attempt at a solution Since the force we provide with our arms shouldn't factor in too much, I did: (m2v2) / r = m1g v = 1.400 m/s t = d / v t = (2pi * 0.545 * 20) / 1.4 t = 48.915 s, which varies WAY too much with the other trials (Each trial, a variable was altered a bit, such as the hanging mass or the radius, but this change only affected the time by 3 seconds or less). The other trials were in the 12.0 - 15.0 s range. What am I doing wrong?