At t1 = 5.00 s, the acceleration of a particle moving at constant speed in counterclockwise circular motion is a1=(2m/s^2)i + (9m/s^2)j At t2 = 6.00 s (less than one period later), the acceleration is a2= (9m/s^2)i - (2m/s^2)j The period is more than 1.00 s. What is the radius of the circle?