1. The problem statement, all variables and given/known data A simple Atwood machine composed of a single pulley and two masses, m1 and m2 is on an elevator. When m1= 44.7kg and m2=45.3kg, it takes 5.00s for mass m2 to descend exactly one meter from rest relative to the elevator. What is the elevator's motion? (That is, is it moving with constant velocity or accelerating up or down? 2. Relevant equations [itex]\Sigma[/itex]F=m*a Y=y0 +v0t+1/2at2 3. The attempt at a solution I found the [itex]\Sigma[/itex]F on m2 [itex]\Sigma[/itex]F on m1 and solved for a, which I took to be the acceleration of mass 2 when the pulley wasn't on the elevator (which I got to be -0.06) Then, I used the kinematic equation to calculate the actual acceleration of mass 2 (which I got to be -0.08 ) Comparing the two, I reasoned that mass 2 was accelerating faster downward on the elevator, which meant some downward force had been applied. Thus, I came to the conclusion that the elevator must have been accelerating downward. I was wrong. It's accelerating upward. Can anyone explain this to me?