The suspension of a car can be considered to form a mass-spring system with a undamped frequency of vibration of 0.09 Hz and a damping ratio, ζ=0.5. The car is driven along a road with dozen, evenly spaced potholes that provide a periodic driving force to the suspension that can be considered as sinusoidal with each peak corresponding to a pothole. If the potholes are spaced a distance 1.2 m apart what speed must the driver avoid driving at to prevent damaging the car?