A disk with a radial line painted on it is mounted on an axle perpendicular to it and running through its center. It is initially at rest, with the line at theta 0 = -90°. The disk then undergoes constant angular acceleration. After accelerating for 3.1 s, the reference line has been moved part way around the circle (in a counterclockwise direction) to theta f = 130°. Given this information, what is the angular speed of the disk after it has traveled one complete revolution (when it returns to its original position at -90°)? http://img175.imageshack.us/img175/6909/picwe9.gif [Broken] here is my work: 360-130=230 degrees. 130(pi/180)=2.26 radians 230(pi/180)=4.014 radians theta=Wot + at^2 /2 4.014 = a (9.61)/2 9.61a = 8.09 a1=.84 radians 2.26/3.1 = .73 rad/s a2=.73 radians .84 + .73 = 1.57 rad/s I found the acceleration of the first 130 degrees; the acceleration of the last 230 degrees, added them, but my answer is wrong. any idea why?