solve the wave equation utt=4uxx for a string of length 3 with
both ends kept free...
solve the wave equation utt=4uxx for a string of length 3 with
both ends kept free for all time (zero Neumann boundary conditions)
if initial position of the string is given as x(3-x), and initial
velocity is zero.
A string of length L = 1 is held fixed at both ends. The string
is initially deformed into a shape given by u(x, t = 0) = sin^2(πx)
and released. Assume a value of c2 = 1. Find the solution u(x, t)
for the vibration of the string by separation of variables.
1. A string is fixed at both ends. If only the length (L)
increases, then the fundamental frequency goes: (circle one)
up
down
2. If only the tension (T) increases, the fundamental goes:
(circle one)
up
down
3. If only the linear mass density increases, the fundamental
goes: (circle one)
up
down
4. The tension (T) in a string fixed across a 1 m length (L) is
400 Newtons, and the linear mass density of the string is 0.01
kg/m....
A taut string of density p and length b is
fixed at both ends. At a distance 3b/7 from the origin it
is pulled up by an amount h, and at a distance
4b/7 it is pulled down by the same amount. Both points are
released simultaneously.
Describe the motion and the amplitudes of the normal modes (So,
which modes are not excited and why not)
A string with a length of 35 cm is fixed at both ends. Waves
travel along it at a speed of 4 m/s.
What is the frequency of its lowest mode of standing
waves?
At what distance from the end of the string is the first node if
the string is vibrating at four times its fundamental
frequency?
If friction is present, the wave equation takes the form utt −
c2 uxx = −r ut, where the resistance r > 0 is a constant.
Consider a periodic source at one end: u(0, t) = 0, u(l, t) = Aeiωt
.
(a) Show that the PDE and the BC are satisfied by u(x, t) =
Aeiωt sin βx sin βl , where β2c2 = ω2 − irω.
(b) No matter what the IC, u(x, 0) and ut(x, 0), are,...
For the wave equation, utt = c2uxx, with the following boundary
and initial conditions,
u(x, 0) = 0
ut(x, 0) = 0.1x(π − x)
u(0,t) = u(π,t) = 0
(a) Solve the problem using the separation of variables.
(b) Solve the problem using D’Alembert’s solution. Hint: I would
suggest doing an odd expansion of ut(x,0) first; the final solution
should be exactly like the one in (a).
Consider an elastic string of length L whose ends are
held fixed. The string is set in motion with no initial velocity
from an initial position
u(x, 0) =
f(x).
Let
L = 10
and
a = 1
in parts (b) and (c). (A computer algebra system is
recommended.)
f(x) =
16x
L
,
0
≤
x
≤
L
4
,
4,
L
4
<
x
<
3L
4
,
16(L −
x)
L
,
3L
4...
6. Consider the one dimensional wave equation with boundary
conditions and initial conditions:
PDE : utt = c 2 uxx, BC : u(0, t) = u(L, t) = 0, IC : u(x, 0) =
f(x), ut(x, 0) = g(x)
a) Suppose c = 1, L = 1, f(x) = 180x 2 (1 − x), and g(x) = 0.
Using the first 10 terms in the series, plot the solution surface
and enough time snapshots to display the dynamics of the...