A rotor consists of four horizontal blades each of length L = 4m and mass m = 90 kg cantilevered off of a vertical shaft. Assume that each blade can be modeled as having its mass concentrated at its midpoint. The rotor is initially at rest when it is subjected to a moment M =\beta t, with \beta = 60N.m/s. Determine the angular speed of the rotor after 10 s.