Equation of an oscillating system without any starting values

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The discussion focuses on deriving the equations of motion for a mass m1 on a platform with mass M, connected to springs with constant k. The participants explore the motion equation, leading to the conclusion that it can be expressed as x(t) = x0*cos(ωt) + (v0/ω)*sin(ωt), while emphasizing the importance of defining the equilibrium position correctly. They also discuss the maximum force on the spring and the normal force between the two masses, noting that the total mechanical energy must be considered. The conversation highlights the need for clarity in defining variables and the relationships between forces in the system. Ultimately, the right approach involves recognizing the inhomogeneous nature of the differential equation due to gravitational effects.
  • #31
RiotRick said:
Update if anyone runs into the same problem. I don't have a solution but the attempt here is wrong. Right attempt would be ##x''m = -kx + m*g## Which leads to an inhom. diff. equation.

With this I close this thread o7
No, as I wrote in post #4 it depends how you define the position x=0. If you define it as being the equilibrium position then that is mg/k below the relaxed spring position. Thus the force in the spring is -k(x-mg/k) = -kx+mg. The net force on the object is thus (-kx+mg)-mg = -kx.
 

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