Man I hate Albert.io:

A CD initially rotating at 23 rad/sec slows to a stop as it rotates through 3 rotations. What is the magnitude of its angular acceleration?
Can I see how you did it too please?
Answers:
A.-1.2rad/s^2
B.-3.8rad/s^2
C.-14rad/s^2
D.-88rad/s^2