PHY 711 Classical Mechanics and Mathematical Methods

MWF 10 AM-10:50 AM OPL 103 http://www.wfu.edu/~natalie/f18phy711/

Instructor: Natalie Holzwarth Phone:758-5510 Office:300 OPL e-mail:natalie@wfu.edu


Course schedule

(Preliminary schedule -- subject to frequent adjustment.)
DateF&W ReadingTopic AssignmentDue
1 Mon, 8/27/2018Chap. 1 Introduction #19/7/2018
Wed, 8/29/2018No class
2 Fri, 8/31/2018Chap. 1 Scattering theory #29/7/2018
3 Mon, 9/03/2018Chap. 1 Scattering theory
4 Wed, 9/05/2018Chap. 1 Scattering theory #39/10/2018
5 Fri, 9/07/2018Chap. 2 Non-inertial coordinate systems #49/12/2018
6 Mon, 9/10/2018Chap. 3 Calculus of Variation #59/12/2018
7 Wed, 9/12/2018Chap. 3 Calculus of Variation #69/17/2018
Fri, 9/14/2018No class University closed due to weather.
8 Mon, 9/17/2018Chap. 3 Lagrangian Mechanics #79/19/2018
9 Wed, 9/19/2018Chap. 3 and 6 Lagrangian Mechanics and constraints #89/24/2018
10 Fri, 9/21/2018Chap. 3 and 6 Constants of the motion
11 Mon, 9/24/2018Chap. 3 and 6 Hamiltonian formalism #99/28/2018
12 Wed, 9/26/2018Chap. 3 and 6 Liouville theorem #1010/3/2018
13 Fri, 9/28/2018Chap. 3 and 6 Canonical transformations
14 Mon, 10/1/2018Chap. 4 Small oscillations about equilibrium #1110/5/2018
15 Wed, 10/3/2018Chap. 4 Normal modes of vibration
16 Fri, 10/5/2018Chap. 1-4, 6 Review
17 Mon, 10/8/2018Chap. 7 Strings
18 Wed, 10/10/2018Chap. 7 Wave equation
Fri, 10/12/2018No class Fall break
19 Mon, 10/15/2018Chap. 7 Wave equation
20 Wed, 10/17/2018Chap. 7 Fourier Transforms #1210/22/2018
21 Fri, 10/19/2018Chap. 7 Laplace transforms; Contour integrals #1310/24/2018
22 Mon, 10/22/2018Chap. 7 Contour integrals
23 Wed, 10/24/2018Chap. 5 Rigid body motion #1410/26/2018
24 Fri, 10/26/2018Chap. 5 Rigid body motion #1510/31/2018
25 Mon, 10/29/2018Chap. 8 Mechanics of elastic membranes #1611/02/2018
26 Wed, 10/31/2018Chap. 9 Mechanics of three dimensional fluids
27 Fri, 11/02/2018Chap. 9 Mechanics of fluids #1711/07/2018
28 Mon, 11/05/2018Chap. 9 Sound waves Project topic
29 Wed, 11/07/2018Chap. 9 Sound waves #1811/12/2018
30 Fri, 11/09/2018Chap. 9 Linear and non-linear sound
31 Mon, 11/12/2018Chap. 10 Surface waves #1911/16/2018
32 Wed, 11/14/2018Chap. 10 Surface waves -- nonlinear effects
33 Fri, 11/16/2018Chap. 11 Heat conductivity #2011/26/2018
34 Mon, 11/19/2018Chap. 13 Elastic media
Wed, 11/21/2018No class Thanksgiving holiday
Fri, 11/23/2018No class Thanksgiving holiday
35 Mon, 11/26/2018Chap. 12 Viscous fluids
36 Wed, 11/28/2018Chap. 12 Viscous fluids
37 Fri, 11/30/2018 Review
Mon, 12/03/2018 Presentations I
Wed, 12/05/2018 Presentations II
Fri, 12/07/2018 Presentations III

PHY 711 – Assignment #1

08/27/2018

  1. Use maple or mathematica to plot the functions
                               ∫
        -x2                  x
f(x) = e      and   h(x) =  0 f (t) dt.

    and to numerically evaluate f(5) and h(5).


PHY 711 -- Assignment #2

Aug. 31, 2018

Read Chapter 1 in Fetter & Walecka.


PHY 711 -- Assignment #3

Sept. 5, 2018

Continue reading Chapter 1 in Fetter & Walecka.


PHY 711 -- Assignment #4

Sept. 7, 2018

Read Chapter 2 in Fetter & Walecka.


PHY 711 -- Assignment #5

Sept. 10, 2018

Start reading Chapter 3, especially Section 17, in Fetter & Walecka.


PHY 711 – Assignment #6

September 11, 2018

This exercise is designed to illustrate the differences between partial and total derivatives.

  1. Consider an arbitrary function of the form f = f(q,˙q,t), where it is assumed that q = q(t) and ˙q dq∕dt.
    1. Evaluate
      ∂ df    d ∂f
------  -----.
∂q dt   dt∂q

    2. Evaluate
      ∂-df--  d-∂f-.
∂ ˙q dt  dt∂ ˙q

    3. Evaluate
      df
---.
dt

    4. Now suppose that
                   2 2                   -t∕τ
f (q,q˙, t) = qq˙t ,  where   q(t) = e   .

      Here τ is a constant. Evaluate df∕dt using the expression you just derived. Now find the expression for f as an explicit function of t (f(t)) and take its time derivative directly to check your previous results.


PHY 711 – Assignment #7

September 16, 2018

  1. Consider a Lagrangian describing the motion of a particle of mass m and charge q given by
                       1  (            )   q
L(x,y, z, ˙x, ˙y,z˙) =-m  x˙2 + y˙2 + ˙z2  + --By˙x.
                   2                   c

    Here c denotes the speed of light and B represents the magnitude of a constant magnetic field along the z-axis. Determine the Euler-Lagrange equations of motion for the particle and discuss how the motion compares with the similar example discussed in class.


PHY 711 – Assignment #8

9/19/2019

Continue reading Chapters 3 and 6 in Fetter and Walecka.

PIC

  1. The figure above shows a box of mass m sliding on the frictionless surface of an inclined plane (angle θ). The inclined plane itself has a mass M and is supported on a horizontal frictionless surface. Write down the Lagrangian for this system in terms of the generalized coordinates X and s and the fixed constants of the system (θ, m, M, etc.) and solve for the equations of motion, assuming that the system is initially at rest. (Note that X and s represent components of vectors whose directions are related by the angle θ.)


PHY 711 -- Assignment #9

Sept. 24, 2018

Continue reading Chapters 3 and 6 in Fetter & Walecka.


PHY 711 -- Assignment #10

Sept. 25, 2018

Continue reading Chapters 3 and 6 in Fetter & Walecka.


PHY 711 -- Assignment #11

Oct. 1, 2018

Start reading Chapter 4 in Fetter & Walecka.

  1. Consider the the mass and spring system described by Eq. 24.1 and Fig. 24.1 in Fetter & Walecka. Explicitly consider the case of N=4 and find the 4 coupled equations of motion. Compare the normal mode eigenvalues for this case (obtained with the help of Maple or Mathematica) with the equivalent analysis given by Eq. 24.38.

PHY 711 – Assignment #12

10/17/2018

Continue reading Chapter 7 in Fetter and Walecka.

  1. A function which is periodic in the length L is given by
                   ∞
f (x) ≡ √-1-- ∑    exp(- (x + nL)2∕a2),
          πa n=- ∞

    where a is a real constant.

    1. Find the Fourier transform F(q), of f(x).
    2. Find a convenient notation to enumerate the discrete values of q.
    3. Write an expression to evaluate the largest value of q needed such that the F(q)∕F(0) 0.01.

10/19/2018

PHY 711 – Homework # 13

Read Appendix A of Fetter and Walecka.

  1. Assume that a > 0 and b > 0; use contour integration methods to evaluate the integral:
    ∫ ∞  cos(ax)
    --4----4dx.
 0  x  + 4b


PHY 711 -- Assignment #14

Oct. 24, 2018

Start Chapter 5 in Fetter & Walecka.

the above figure shows an object with four particles held together with massless bonds at the coordinates shown. The masses of the particles are m1=m2 ≡ 2m and m3=m4 ≡ m.

  1. Evaluate the moment of inertia tensor for this object in the given coordinate system.
  2. Find the principal moments of inertia and the corresponding principal axes. Sketch the location of the axes.

PHY 711 -- Assignment #15

Oct. 26, 2018

Continue reading Chapter 5 in Fetter & Walecka.

  1. Work problem 5.9 at the end of Chap. 5 of Fetter & Walecka.

PHY 711 -- Assignment #16

Oct. 29, 2018

Read Chapter 8 in Fetter & Walecka.

  1. Work problem 8.5 at the end of Chap. 8 in Fetter & Walecka

PHY 711 -- Assignment #17

Nov. 2, 2018

Continue reading Chapter 9 in Fetter & Walecka.

  1. Determine the form of the velocity potential for a 3-dimensional incompressible fluid which flows at uniform velocity in the z direction at large distances from a spherical obstruction of radius a. Find the form of the velocity potential and the velocity field for all r > a. Assume that the velocity in the radial direction is 0 for r = a and assume that the velocity is uniform in the azimuthal direction.

PHY 711 -- Assignment #18

Nov. 7, 2018

Continue reading Chapter 9 in Fetter & Walecka.

  1. Consider the approximate result given in Eq. 51.76 of your text book. Show how the result follows from evaluation of Eq. 51.74 when ka << 1.

PHY 711 -- Assignment #19

Nov. 12, 2018

Start reading Chapter 10 in Fetter & Walecka.

  1. Work Problem 10.3 at the end of Chapter 10 in Fetter and Walecka.

PHY 711 -- Assignment #20

Nov. 16, 2018

Start reading Chapter 11 in Fetter & Walecka.

  1. Consider the rectangular heat conduction problem discussed in Lecture 33, starting with slide 9. Suppose that at time t=0, the temperature profile is

    T(x,y,z,0) = T0(1 + sin(πx/a)).

    At what later time t does the rectangle achieve a uniform temperature T0 with a 10 % fluctuation when the rectangle is made of
    1. copper
    2. air
    You may use the values of thermal diffusivity quoted in class. Assume that a = 0.1 m.




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Last modfied: Saturday, 17-Nov-2018 17:38:00 EST