One part of a fireworks display uses a 0.10-meter-square platform, on which four tubes of gunpowder are mounted along the platforms edge. As the powder burns, the square spins about an axis that is perpendicular to its center. The unit reaches an angular speed of 31 rad/s in one-half second, starting from rest, because each of three tubes generates a force of 0.30 Newton's and the fourth tube generates an unknown force. Assume that the moment of inertia of the entire unit has a constant value of 1.0 X 10^-3 kg X m^2 and that the forces are constant. What is the magnitude of the force generated by the fourth tube?