Solving a Steam Engine Flywheel Angular Displacement Problem

[jcfor3ver]

Homework Statement

The flywheel of a steam engine begins to rotate from rest with a constant angular acceleration of 1.33 rad/s2. It accelerates for 23.5 s, then maintains a constant angular velocity. Calculate the total angle through which the wheel has turned 67.3 s after it begins rotating.

Homework Equations

Using kinematic equations (I just replace the variables with angular variables, such as velocity will actually be represented with and omega symbol)

Vf = Vi + at
Vf^2 = Vi^2 + 2ax Vi = initial velocity
x = ViT + .5at^2 a = acceleration
x = displacement
vf = final velocity
t = time

The Attempt at a Solution

So first off, I found how far the flywheel thing has traveled. I knew it accelerated for 23.5 seconds, so I used the equation for distance=.5*a*t^2. This number I got was 367.24625, which I used as my theta initial val. Then I proceeded to find the velocity (omega) at 23.5 seconds (since it is constant after that time) and using the equation above for vel. I got 31.255 (I took the accel and multiplied it by the time 23.5 s).
This gave me my Vf, or Omega final which is 31.255 rad/sec.

My total time is 67.3 s, but since I acceled the first 23.5 s and got values for that time interval, I took my delta time as 67.3-23.5 s and got 43.8 s.

So Theta initial= 367.24625 deg
Omega final= 31.255 rad/sec (constant)
Delta Time= 43.8 sec
And my accel=0 during this time interval

I used the equation theta f= theta i + .5(omega)(delta time) and got 1051.73075 deg. I've tried many other ways and still cannot get the right answer. The computer tells me if the answer is right or wrong.

HELP PLZ!

 

[rl.bhat]

In the second part acceleration is zero.
So total angle is θf = θi + ω*t2.( t2 = 43.8 s)