A motorcycle, which has an initial linear speed of 9.7 m/s, decelerates to a speed of 2.6 m/s in 3.6 s. Each wheel has a radius of 0.69 m and is rotating in a counterclockwise (positive) directions. What is (a) the constant angular acceleration (in rad/s2) and (b) the angular displacement (in rad) of each wheel?