1. The problem statement, all variables and given/known data Two uniform disks with the same mass are connected by a light inextensible string supported by a massless pulley, on a frictionless axis. The string is attached to a point on the circumference of disk A. The string is wound around disk B so that the disk will rotate like a yo-yo when dropped. Describe the outcome when both disks hit the floor. 2. Relevant equations -ma=T-mg Tr=(1/2)mr^2(alpha) 3. The attempt at a solution Okay I know that the two tensions are equal because the pulley is massless. I wanted to prove it to myself with equations which is the right answer. I decided that the translation accelerations for each mass would be different because one has the string wound around it and the other is simply hanging by the string. I wasn't sure though what to make the direction of both accelerations, I just assumed negative for the calculations below: Disk A -ma=T-mg Disk B Tr=1/2mr^2(A/r) T=mA/2 -mA=T-mg I substituted T=mA/2 into the second equation for disk B to get: -mA=mA/2 - mg mA=mg- mA/2 3A/2=g A= 6.53 Then I solved for T and just put the mass as 1kg T= 6.53/2=3.27 Then I used T to solve for a for disk A -a= 3.27 - 9.8 a= 6.53 Does this seem right at all? They both accelerate the same in magnitude, but opposite in direction? I think I remember being my teacher doing something like a + A = 0, but I may have just imagined it. Confirmation or correction would be amazing! Thanks!