mẍ = −kx .

\sqrt{\frac{k}{m}}

2π / ω

x_{analytic}(t) = x_{0} cos(ωt) . mẍ = −kx − bẋ , mẍ = −kx − c|ẋ|ẋ , θ̈(t) = −ω_{0}^{2} (θ(t) − θ_{off}) − c |θ̇(t)| θ̇(t)

˙ θ