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0 votes
2 answers
63 views

Approximation of Small Perturbation [closed]

From Morin's Classical Mechanics, on the chapter of Small Oscillations in Lagrangian Mechanics, he does this approximation on the last equality, I don't understand what happened there. I get the first ...
Lyu's user avatar
  • 109
5 votes
2 answers
922 views

Rigorously prove the period of small oscillations by directly integrating

This answer proved that $$\lim_{E\to E_0}2\int_{x_1}^{x_2}\frac{\mathrm dx}{\sqrt{2\left(E-U\!\left(x\right)\right)}}=\frac{2\pi}{\sqrt{U''\!\left(x_0\right)}},$$ where $E_0:=U\!\left(x_0\right)$ is a ...
Ulysses Zhan's user avatar
11 votes
3 answers
2k views

Why do we ignore the second-order terms in the following expansion?

Consider the expansion done for the kinetic energy of a system executing small oscillations as done in Goldstein: A similar series expansion can be obtained for the kinetic energy. Since the ...
Deepanshu Chaudhary's user avatar
1 vote
3 answers
2k views

Second derivative of energy as frequency of oscillations [closed]

Is there a way to algebraically see why when I take the second derivative of a potential energy in a point where it is minimal (force is zero), I generally get the frequency (squared) of the ...
Darkenin's user avatar
  • 1,028