Talk:Series and parallel springs

Justification for article

This article used to be a couple of sections in Hooke's law and spring (device). Note that there is a series and parallel circuits for the electrical analogues. Today that article is far longer than this one, as it covers resistors, capacitors, inductors, etc. Hopefully this article will grow to include at least series and parallel "dashpots" (a dashpot being a combination of spring and damper). --Jorge Stolfi (talk) 15:04, 25 January 2013 (UTC)

Series derivation

(From Talk:Hooke's law --Jorge Stolfi (talk) 15:07, 25 January 2013 (UTC))

Isn't it too deliberate? As far as I understand, it is enough to observe that the force on both springs is equal and that the total length equals to sum of springs' respective lengths.
I.e.

s = s1 + s2     (1)
F=F1=F2     (2)
Plug in s=F/k in (1) and get F/k= F1/k1 + F2/k2.
From (2) we see that we can divide with F and get 1/k= 1/k1 +1/k2.

Btw sorry for no latex. I'm writing this from my cellphone.
89.201.134.178 (talk) 23:04, 20 December 2009 (UTC)

• I reformatted the above, in place, to the extent of indentation, line breaks, and spacing. At a glance, i can't tell whether it's been incorporated into the accompanying article, so i construe the following as intended by the above:
  

s = s₁ + s₂     (1)
F = F₁ = F₂     (2)
Plug in s = F/k in (1) and get F/k = F₁/k₁ +F₂/k₂.
From (2) we see that we can divide with F and get 1/k = 1/k₁ +1/k₂.

--Jerzy•t 20:33, 10 March 2010 (UTC)

Series spring derivation

(From Talk:Hooke's law --Jorge Stolfi (talk) 15:22, 25 January 2013 (UTC))

Shouldn't the line;

$F_{b}=-k_{2}\left(x_{2}-x_{1}\right).\quad \quad \quad (1)\,$

Read;

$F_{b}=-k_{eq}\left(x_{2}-x_{1}\right).\quad \quad \quad (1)\,$

k_1 and k_2 haven't been introduced yet
—Preceding unsigned comment added by Nkuzmik (talk • contribs) 19:27, 21 October 2006

Please sign your posts. Stovetopcookies 02:06, 18 November 2006 (UTC)

• As the delay until today demonstrates, the only effective remedy for unsigned posts is use by another editor, w/ subst:, of {{unsigned2ip}} (or, occasionally, as in this case {{unsigned2}}), with the insertion of material cut-and-pasted from the talk page's corresponding edit-history entry. Either a moment's thot, or inspection of this talk page's edit history, will make it obvious that that is most efficiently done when the lapse is first noticed.
  --Jerzy•t 20:07, 10 March 2010 (UTC)
  

A considerably simpler derivation, which relies on the forces on each spring being the same, is here: http://sepwww.stanford.edu/public/docs/sep77/francis2/paper_html/node2.html. Is this sufficiently general? Sketch for 2 springs: Force on spring 1 = F1 = -k1 * x1. Force on spring 2 = F2 (= F1) = -k2 * x2. => -F1/k1 = x1 and -F2/k2 = -F1/k2 = x2. Total extension = x1 + x2 = -(F1/k1 + F1/k2) = -(F1(k2 + k1))/(k1*k2). => F1 = -(k1*k2/(k2+k1))*(x1+x2). => F(eff)=k1*k2/(k1+k2) => 1/F(eff) = 1/k1 + 1/k2. — Preceding unsigned comment added by 202.154.136.162 (talk) 04:30, 25 July 2011 (UTC)

Inconsistent coordinates

(From Talk:Hooke's law --Jorge Stolfi (talk) 15:34, 25 January 2013 (UTC))

In the derivation section "Equivalent Spring Constant" the coordinate system is inconsistent with the coordinate system in the main article. In the main article, the equation x1/x2 = k2/k1 appears in derivtion section the equation x1/x2= k2/(k1 + k2) appears. — Preceding unsigned comment added by Nachtsheim (talk • contribs) 20:37, 21 June 2012 (UTC)

This comment my be irrelevant now that the material has been moved out of Hooke's law.