A string passes over a frictionless, mass less pulley attached to the ceiling. A mass m1 = 15.0 kg hangs from one end of this string, and a second mass less, frictionless pulley hangs from the other end. A second string passes over the second pulley and a mass m2 = 4.0 kg hangs from one end of the string, whereas the other end is attached firmly to the ground. Suppose positive accelerations are upward.
1) What is the acceleration of mass m1? Number m/s^2
2) What is the acceleration of mass m2? Number m/s^2
3) What is the acceleration of the second pulley?