How to get the equation spring equation? Please help me understand

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Discussion Overview

The discussion revolves around deriving a specific equation related to the behavior of a spring under varying mass conditions. Participants explore the relationships between mass, force, and displacement in the context of spring mechanics, seeking clarity on how to manipulate the given equations to arrive at a desired form.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant presents a set of equations involving mass, displacement, and gravitational force, asking how to derive a specific equation from them.
  • Another participant asserts that an additional equation is necessary to relate the spring force to the mass and displacement, specifically mentioning the spring force equation, F = k * extension.
  • A subsequent post questions how to incorporate the spring force equation into the derivation of the desired equation.
  • Another participant attempts to clarify the problem by suggesting that understanding the problem statement is essential before proceeding with the equations.
  • A later reply provides a detailed derivation using the equations of motion and forces, leading to a rearranged form of the original equation, but does not confirm its correctness or address potential issues.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the necessary equations for deriving the desired relationship, with some asserting that additional equations are required while others attempt to derive the equation with the provided information.

Contextual Notes

The discussion highlights potential limitations in the assumptions made regarding the forces acting on the mass and the spring, as well as the need for clarity on the problem statement before proceeding with mathematical manipulations.

madeeeeee
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How do you use the equations

m=Minital + deltaM
and x=xinital + deltax
and F=-mg

to get x=(g/k)deltaM + ((Minital)(g)/k +xinital)

(where m= mass. Minital is fixed inital mass and deltaM is additional weight added)
(where x= displacement. xinital is when no downward force is applied and deltax is displacement from unstretched position)

please explain how to get this equation

Thank you
 
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It can't be done. You need one more equation: Force that the spring exerts on a mass = k * extension.
 
so if I use F=-kdeltax than how can I now show the above equation?
 
Perhaps I can help if I understand the problem better. What was the statement of the problem? The equations can come later.
 
m = mi + Δm
Fg = -mg
so
Fg = -g(mi + Δm)

Fs = kΔx (positive since it is acting against gravity)

We are looking for Δx when the forces cancel so
0 = Fg + Fs
-Fs = Fg
-Fs = Fg = -g(mi + Δm) = -kΔx
devide by -k

Δx = g(mi + Δm)/k

The using x = xi + Δx
substitute Δx, multiply out and rearrange a bit and you get

x=(g/k)Δm + (g/k)mi +xi
 

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