A wheel rotating about a fixed axis has an angular position given by  = 3. 0 − 2. 0t 3 , where  is measured in radians and t in seconds. What is the angular acceleration of the wheel at t = 2. 0 s? a. −1. 0 rad/s2 b. −24 rad/s2 c. −2. 0 rad/s2 d. −4. 0 rad/s2 e. −3. 5 rad/s2