Damped harmonic oscillator for a mass hanging from a spring

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Homework Help Overview

The discussion revolves around the analysis of a damped harmonic oscillator, specifically focusing on a mass hanging from a spring and the effects of an initial hammer blow. Participants explore the general solutions for damped harmonic motion and the implications of initial conditions on the system's behavior.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the application of the general solution for damped harmonic motion, questioning how initial conditions, such as a non-zero initial velocity from a hammer blow, affect the system. There is uncertainty about whether to treat the scenario as a driven harmonic oscillator.

Discussion Status

Some participants provide guidance on interpreting the general solution and emphasize that the hammer blow primarily sets initial conditions rather than driving the oscillator. The conversation reflects an ongoing exploration of the problem without reaching a definitive consensus.

Contextual Notes

There is mention of different cases for damping (underdamped, critically damped, overdamped) and the need to fit the general solution to specific initial conditions. The discussion also highlights the importance of understanding the equilibrium position of the hanging mass.

Phantoful
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Homework Statement


g9XAO77.png


Homework Equations


Complex number solutions
z= z0eαt
Energy equations and Q (Quality Factor)

The Attempt at a Solution


For this question, I followed my book's "general solution" for dampened harmonic motions, where z= z0eαt, and then you can solve for α and eventually getting an answer of x=Ae-(ϒ/2)tcos(ω1t+∅) where ω1=sqrt((ω02-(ϒ/2)2)). This is just for the underdampened case and there are other solutions for the critical and overdampened case. However, I don't think these are the answers and I'm not even sure how to interpret these "general solutions". For this question would the case be any different if a v(0) = v0, and the mass is hanging? Should I treat it like a driven harmonic oscillator because of the hammer? This is the first time I'm answering a question like this one.
 

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All the hammer blow does is to give you a non-zero initial velocity. Otherwise, just solve the ODE for the prescribed conditions.
 
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Phantoful said:

Homework Statement


View attachment 223518

Homework Equations


Complex number solutions
z= z0eαt
Energy equations and Q (Quality Factor)

The Attempt at a Solution


For this question, I followed my book's "general solution" for dampened harmonic motions, where z= z0eαt, and then you can solve for α and eventually getting an answer of x=Ae-(ϒ/2)tcos(ω1t+∅) where ω1=sqrt((ω02-(ϒ/2)2)). This is just for the underdampened case and there are other solutions for the critical and overdampened case. However, I don't think these are the answers and I'm not even sure how to interpret these "general solutions". For this question would the case be any different if a v(0) = v0, and the mass is hanging? Should I treat it like a driven harmonic oscillator because of the hammer? This is the first time I'm answering a question like this one.

The general solution in the book is applicable to your problem. A hanging mass will oscillate about its equilibrium position. x is the deviation from the equilibrium.
Hitting once with the hammer does not mean that the oscillator is driven., It provides the initial conditions you have to fit the general solution to: At t=0 x(0)=0 and v(0)=v0. Determine A and θ for each case.
 
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Thank you!
Dr.D said:
All the hammer blow does is to give you a non-zero initial velocity. Otherwise, just solve the ODE for the prescribed conditions.

ehild said:
The general solution in the book is applicable to your problem. A hanging mass will oscillate about its equilibrium position. x is the deviation from the equilibrium.
Hitting once with the hammer does not mean that the oscillator is driven., It provides the initial conditions you have to fit the general solution to: At t=0 x(0)=0 and v(0)=v0. Determine A and θ for each case.
 

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