A 2 kg mass on a horizontal friction-free air track is accelerated by a string attached to a 100 kg mass hanging vertically from a pulley as shown. Compare the accelerations when the masses are interchanged, that is, for the case where the 100 kg mass dangles over the pulley, and then for the case where the 2 kg mass dangles over the pulley.

acceleration with 100 kg mass dangling g
acceleration with 2 kg mass dangling g

What does this indicate about the maximum acceleration of such a system of masses?