Question: What is the characteristic equation of a second-order system?

Options:

1. s^2 + 2ζω_ns + ω_n^2 = 0
2. s^2 + ω_n^2 = 0
3. s^2 + 2ω_ns + ζ = 0
4. s^2 + 2s + 1 = 0

Correct Answer: s^2 + 2ζω_ns + ω_n^2 = 0

Solution:

The characteristic equation of a second-order system is s^2 + 2ζω_ns + ω_n^2 = 0, where ζ is the damping ratio and ω_n is the natural frequency.