The figure above shows the schematic of an automobile having a mass of 900 kg and the suspension spring constant of 81× 104 N/m. If it travels at a speed at a speed of 72 km/hr on a rough road with periodic waviness as shown, what is the forcing frequency of the road on the wheel?
1
10 Hz
2
4 Hz
3
1.5 Hz
4
20 Hz