In the given figure, a = 15 ``\frac {m}{s^2}`` represents the total
acceleration of a particle moving in the clockwise
direction in a circle of radius R = 2.5 m at a given
instant of time. The speed of the particle is :-

(1) 5.7 m/s
(2) 6.2 m/s
(3) 4.5 m/s
(4) 5.0 m/s