Two blocks of masses m1 and m2 are connected to each other on an Atwood machine (the blocks are connected by a string going over a light pulley with no friction in the bearing). A person holds one of the blocks with her hand. When the system is released, the heavier block moves down with an acceleration of 3.5 m/s2 and the lighter object moves up with an acceleration of the same magnitude. Suppose that the lighter block has a mass of m1 = 100 g. Determine the mass m2.