Radius = 3 m
Centripetal acceleration = 15 m/s^2
We know, centripetal acceleration= square of Velocity/Radius
or, Square of velocity = Centripetal Acceleration× Radius
Therefore, the square of velocity
= (15 × 3) m/s = 45 m/s
Therefore, the speed
= √45 m/s
= √3×3×5 m/s
= 3√5 m/s
The answer is 3√5 m/s.