1. The problem statement, all variables and given/known data The 100 kg block shown in the diagram takes 6.0s to reach the floor 1.0m below after being released from rest. What is the mass of the block on the left? 2. Relevant equations Newton's Third Law F=ma F (a on b) = -F (b on a) 3. The attempt at a solution I don't even know where to start, I was sick last class and can't figure out how to do this from the textbook. I've tried so far: T1 = tension rope 1 T2 = tension rope 2 t0= 0s t1= 6s d=1.0m g=9.8m/s^2 m1=unknown, find m2=100kg mass M: Fy = 0 T1-mg=0 T1=mg T2= mg = (100kg)(9.8m/s^2) = 980N And now I'm lost.