The drive propeller of a ship starts from rest and accelerates at 2.50 x 10-3 rad/s2 for 2.15 x 103 s. For the next 1.85 x 103 s the propeller rotates at a constant angular speed. Then it decelerates at 2.30 x 10-3 rad/s2 until it slows (without reversing direction) to an angular speed of 4.00 rad/s. Find the total angular displacement of the propeller.