## Lecture notes

Lecture 19, Dec. 1: Inertia tensors and non-linear physics.

One correction in page 12: $\omega_N \rightarrow \omega_N^2$.

Lecture 18, Nov. 29: Coupled Oscillator examples and rigid body.

One correction in page 4. Thanks, IL!

Two corrections in page 9. Thanks, NS!

Lecture 17, Nov. 22: Coupled oscillators. (Qs)

One correction in page 3. Thanks, MD!

Lecture 16, Nov. 17: Coupled oscillators.

Some footnotes and several sentences added. — Sam,

*11:15AM, Nov 18, 2011*

Lecture 15, Nov. 15: Collisions, impact parameter, crossection.

Correction: Figure on page 6. $dA/\cos \theta$. –

*3:13PM, Nov 23, 2012*Correction: on page 8. One typo. Thanks, DL!

'Typically but not always,' added in page 7 (red).

'short' added in page 1 (red). Thanks, PW!

Lecture 14, Nov. 10: Kepler problem and many particle system.

Two corrections: page 8, top. Thanks, IG!

Lecture 13, Nov. 8: Kepler problem. (Qs)

Correction: page 2, $L_{M} \rightarrow L_{cm}$.

Lecture 12, Nov. 3: Gravity. (Qs)

Lecture 11, Nov. 1: Lagrangian with constraint, Effective potential, Gravity.

Lecture 10, Oct. 25: Hamiltonian. Lagrangian with constraint. (Qs)

Lecture 9, Oct. 20: Symmetry and conservation. Momentum and angular momentum. (Qs)

One correction in page 4. Thanks, NS!

Addition in page 6: Added "$\delta L =$".

Lecture 8, Oct. 18: Principle of least action. (Green’s function method – solutions)

Page numbers corrected. — Sam,

*2:25PM, Oct 25, 2011*

Lecture 7, Oct. 13: Driven oscillations. (Qs)

Lecture 6, Oct. 11: Small oscillations, free or damped. (Qs)

Lecture 5, Oct. 6: Conservation principles and 1D motions.

Correction: on page 7. A bunch of sqrt notations corrected. Thanks, AM!

Lecture 4, Oct. 4: Lorentz force. (Qs)

- Read footnote 3, to clear up the confusion for the number of integration constants.
When we consider the time-reversal symmetry of this problem, we do not reverse the direction of $\vec{B}$, taking it as given. If we can reverse the direction of $\vec{B}$ as well as the direction of the particle's motion, then the time reversal symmetry would be valid. Read end of page 4, to see why sometimes $\vec{B}$ is not reversible.

Lecture 3, Sep. 29: Perturbation. Air resistance. (Qs)

Correction: Page 8, a new box on perturbation expansion. 2/3 → 1/3 in 3 lines above the box. — Sam,

*1:04PM, Oct 04, 2011*

Lecture 2, Sep. 27: Newton's laws. Air resistance. (Qs)

Lecture 1, Sep. 22: What to learn? Particles, dimensions. Vectors and (orthogonal) matrices.

## Appendices

- Page 5 and examples are important.
Correction: Page 8, $gt$ → $g$ for the first term in the equation for $\dot{v}$ from 2nd order and higher. Thanks, JW. You will get 10 % "LN debug bonus" on the current homework (#8). — Sam,

*1:45AM, Nov 23, 2011*