The simulation of a rotating wheel below shows the relationship between angular position, angular velocity, and angular acceleration.  Graphs of angular position and angular velocity as a function of time are shown.

If the wheel has a negative initial angular velocity and slows down (angular speed decreases), is the angular acceleration positive or negative?

For each of the following simulations, decide whether the angular velocity is positive, negative, or zero and whether the angular acceleration is positive, negative, or zero.