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PatsyTy
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Homework Statement
Consider two masses m connected to each other and two walls by three springs with spring constant k. The left mass is subject to a driving force ## F_d\cos(2 \omega t) ## and the right to ## 2F_d\cos(2 \omega t) ##
Homework Equations
Writing out the coupled equations:
$$ m_1 x_1''+2kx_1-kx_1 = F_d \cos (2\omega t) $$
$$ m_2 x_2''-kx_1+2kx_2 = 2F_d\cos (2 \omega t) $$
The Attempt at a Solution
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Assume a solution
$$ x_1 = A_1 \cos (\omega t) \rightarrow x_1'' = -A_1 \omega^2 \cos (\omega t) $$
$$ x_2 = A_2 \cos (\omega t) \rightarrow x_2'' = -A_2 \omega^2 \cos (\omega t) $$
Sub this into our original equation and write it as a matrix equation
$$ -\omega^2 \cos (\omega t) \left( \begin{array}{c} A_1 \\ A_2 \end{array} \right) + \omega^2 \left( \begin{array}{cc} 2 & -1 \\ -1 & 2 \end{array} \right) \left( \begin{array}{c} x_1 \\ x_2 \end{array} \right) = \frac{F_d}{m} \cos (2 \omega t) \left( \begin{array}{c} 1 \\ 2 \end{array} \right) $$
where ##\omega^2 = k/m ##. This is where I get stuck, before we would form an eignevalue problem and solve the characteristic polynomial to get the eigenvalues then the constants ##A_1## and ##A_2## however we have too many terms to do this.
A suggestion on where to go from here would be greatly appreciated!
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