The solution for this problem is through this formula:Ø = w1 t + 1/2 ã t^2 where:Ø - angular displacement w1 - initial angular velocity t - time ã - angular acceleration 128 = w1 x 4 + ½ x 4.5 x 5^2 128 = 4w1 + 56.254w1 = -128 + 56.25 4w1 = 71.75w1 = 71.75/4 w1 = 17.94 or 18 rad s^-1 w1 = wo + ãt w1 - final angular velocity wo - initial angular velocity 18 = 0 + 4.5t t = 4 s