Two blocks with masses M1 and M2 hang one under the other with M1 over M2. take the positive direction to be upward, and use (9.8) for the magnitude of the acceleration due to gravity.
a) if the blocks are at rest, what is the tension, T2 in the lower rope.
b) what is T1 in the upper rope?
c) If the blocks are now accelerating upward (due to the tension in the strings) with acceleration of magnitude a. Find T2, the tension in the lower rope and T1, the tension in the upper rope.