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ssulun
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Homework Statement
See attachment.
f(t) is the input force and b1 and b2 are kinetic friction constants. There is no static friction.
Homework Equations
[tex]ƩF = m \ddot{x}[/tex]
[tex]F_s=kx[/tex]
[tex]F_f=b\dot{x}[/tex]
Ff is the force from friction and Fs is the force from spring.
The Attempt at a Solution
[tex]m_1\ddot{x_1}=-b_1\dot{x_1}-k_1x_1-k_1x_2[/tex]
[tex]m_2\ddot{x_2}=-b_2\dot{x_2}-k_1x_1-k_1x_2-k_2x_2[/tex]
[tex]m_3\ddot{x_3}=f[/tex]
I have two questions:
1) Should I include the friction between m1 and m3 and m2 and m3 in the equation for x3 and why?
2) When I imagine this system, I think that f(t) should definitely affect x1 and x2, but in my equations it doesn't. Where am I doing wrong?
Thanks in advance.
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