Differential Equations Eigenvalue!!!

g4gate

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Jun 9, 2009
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Consider the double mass spring system shown in the figure below.



homework5-prob10-sfig5-3-1.gif



The positions and of the two masses are given by the system

a250b77450cbd97cf98bd80fcd13bd1.png



Let
05fffb2b801ce95c76a80fc4a7ef6b1.png
and . If the forcing imparts a force
f4550a18e153363d8a2496243a8d041.png
on the first mass and a force
bb29611c9b7d5c2055feb62e09d3091.png
on the second and the masses start from rest (
e5db9f7900ae2f1f6a1fddf557324a1.png
) and at their equilibrium positions (
9fe8128e54ea035c56995e0baed2a91.png
), find the resulting motion of the system.
d06bd52058a25a64bfc5d0b7a484251.png



Attempt:

First I found the eigen values which are 16 and 24. Then found the respective eigenvectors:

for lambda = -9 v1 = 1 1

for lambda = -25 v2 = -1 1

So,

After that I am stuck... Please help...

Many Thanks!!!
 
g4gate said:
Consider the double mass spring system shown in the figure below.



homework5-prob10-sfig5-3-1.gif



The positions and of the two masses are given by the system

a250b77450cbd97cf98bd80fcd13bd1.png



Let
05fffb2b801ce95c76a80fc4a7ef6b1.png
and . If the forcing imparts a force
f4550a18e153363d8a2496243a8d041.png
on the first mass and a force
bb29611c9b7d5c2055feb62e09d3091.png
on the second and the masses start from rest (
e5db9f7900ae2f1f6a1fddf557324a1.png
) and at their equilibrium positions (
9fe8128e54ea035c56995e0baed2a91.png
), find the resulting motion of the system.
d06bd52058a25a64bfc5d0b7a484251.png



Attempt:

First I found the eigen values which are 16 and 24. Then found the respective eigenvectors:

for lambda = -9 v1 = 1 1

for lambda = -25 v2 = -1 1

So,

After that I am stuck... Please help...

Many Thanks!!!

DUPLICATE POST:

http://www.mathhelpforum.com/math-help/ ... ystem.html

Your problem asks you to: find the resulting motion of the system

What is it that they are looking for? Please explain what do you understand by the term "resulting motion"?
 
Subhotosh Khan said:
Your problem asks you to: find the resulting motion of the system

What is it that they are looking for? Please explain what do you understand by the term "resulting motion"?

I just have to find the solution x_1 and x_2
 
The eigen values you found - how can those be used in your "stiffness matrix" of the original equation?

Using those eigenvalues - you would uncouple the DE - and the solution is simple then.
 
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