Final answer:
True, an undamped spring-mass system shows resonance when excited by impulses at intervals matching its natural period, amplifying oscillations.
Step-by-step explanation:
The statement that an undamped spring-mass system exhibits a resonance-like behavior if it is excited by repeated impulse functions applied at intervals equal to the natural period of the system is True.
A system's natural frequency is the frequency at which the system will oscillate if not affected by driving or damping forces. When a periodic force driving a harmonic oscillator at its natural frequency is applied, the system is said to resonate. This causes the amplitude of the oscillations to increase with each successive impulse because each one adds energy to the system at the optimal time. The less damping a system has, the higher the amplitude of the forced oscillations near resonance. If the impulses are applied at the system's natural period, which is the inverse of the natural frequency, resonance occurs because the timing of impulses matches the system's intrinsic periodicity.