The critical speeds of an automobile are the speeds at which resonance occurs. To calculate the response of the automobile at 54 km/h using the modal analysis approach, more information is needed about the suspension system and driving frequency.
The critical speeds of an automobile are the speeds at which resonance occurs. Resonance is when the driving frequency matches the natural frequency of the system, causing a large-amplitude oscillation. To find the response of the automobile when traveling at 54 km/h using the modal analysis approach, we need to determine the natural frequency of the car's suspension system and the driving frequency at that speed.
Since this question does not provide any information about the suspension system or the driving frequency of the car at 54 km/h, it is not possible to calculate the response using the modal analysis approach.