1. The problem statement, all variables and given/known data I have a problem about two masses: m1 sitting on a table and m2 hanging off the end of th table across a frictionless pulley. There is friction between m1 and the table, however. The system is released from rest and m2 falls 1 meter in 1.2 seconds. m1=10.0 kg, m2=5.00 kg. find the coefficient of kinetic friction. 2. Relevant equations I used x=.5at^2 to find a. I used m2g - T = m2a for m2 with down being positive and up being negative. And I used T - (mu)m1g = m1a for m1 with positive being the direction toward the end of the table. 3. The attempt at a solution I used x=1 meter, t = 1.2 seconds in the first equation and solved for a to get a = 1.39 m/s^2. Then I solved the next two equations for T, set them equal to each other, then solved for mu to get mu = (m2g - m2a - m1a) / (m1g). This gave me a negative value for mu (-0.163) and I know that mu should be positive. Thanks for your help.