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?


q = q0 + w0t + (1/2)at2

q0 rad

w0 rad/s

a rad/s2


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.

Example 1 Example 2 Example 3 Example 4 Example 5