Final answer:
The amplitude of vibration of an undamped system is the maximum displacement from the equilibrium position, and it remains constant if the system is undamped. However, without specific initial conditions or context, the exact amplitude cannot be determined from the provided options.
Step-by-step explanation:
The amplitude of vibration of an undamped system refers to the maximum displacement from the equilibrium position that the system can achieve during its oscillation. Since an undamped system doesn't lose energy over time, its amplitude remains constant throughout the motion. Therefore, if the system you're inquiring about is undamped and the initial conditions specify an amplitude, that amplitude will be the extent of vibration throughout the system's motion. However, you provided options for amplitude (1mm, 2mm, 0.5mm, 5mm) without specifying initial conditions, and without additional context or values, it is not possible to definitively state the amplitude of vibration for the system. It depends entirely on the initial displacement or initial conditions of the system.