Is K2 Positive in the Spring Mass Damper State Space Equations?

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Discussion Overview

The discussion revolves around the state space equations for a spring-mass-damper system, specifically questioning the sign of the spring constant K2 in the context of dynamic equations. Participants are exploring the formulation of these equations and the implications of K2 being positive or negative.

Discussion Character

  • Technical explanation, Homework-related, Debate/contested

Main Points Raised

  • One participant seeks confirmation on the validity of their dynamic equation for a mass in a spring-mass-damper system.
  • Another participant emphasizes the importance of doing the work independently and suggests sharing specific attempts to facilitate assistance.
  • A participant mentions using the Lagrange method but indicates difficulties in fitting the equations into state space form.
  • There is a question about whether the tensile force K2 in the spring should be considered positive or negative.
  • Some participants assert that K2 should be positive, while another questions the assumption that all forces are positive and sum to zero.

Areas of Agreement / Disagreement

There is no consensus on the sign of K2, with some participants asserting it should be positive while others express uncertainty about the conditions under which this holds true.

Contextual Notes

The discussion may be limited by the lack of specific details regarding the dynamic equations and the assumptions underlying the participants' claims about the forces involved.

z_e_u_s
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I'm sorry that post my problem picture, there is a reason that our lecturer doesn't allow this,
he can find this problem using keyword included in question.

the problem is i want to write state space equations also output. the sate variables x1 v1 and theta

dynamic equation for mass
m77x34.png


i want to konw this equation is true or not?
 
Last edited:
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welcome to pf!

hi z_e_u_s! welcome to pf! :wink:
z_e_u_s said:
… there is a reason that our lecturer doesn't allow this,
he can find this problem using keyword included in question.

sorry, but on this forum you need to do the work yourself :redface:

show us what you've tried, and where you're stuck, and then we'll know how to help! :smile:
 
yes i tried but homework has one question and 18 parts
the other parts related with first part.
i try to use lagrange method and equations doesn't fit the sate space...
 
i stuck in that equation
m77x34.png


is this dynamic equation for mass

or K2springs tensile force be positive not negative?
 
K2 should be positive
 
henlus said:
K2 should be positive

Are you sure the all forces are positive then equals to zero...
 

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