At t1 = 1.00 s, the acceleration of a particle moving at constant speed in counterclockwise circular motion is a1 = (10.0 m/s^2)i + (9.00 m/s^2)j. At t2 = 4.00 s (less than one period later), the acceleration is a2 = (9.00 m/s^2)i - (10.0 m/s^2)j.
The period is more than 3.00 s. What is the radius of the circle?