F(adsbygoogle = window.adsbygoogle || []).push({}); _{W}+(Spring Force 2)K_{2}N_{2}(D_{2}-Delta)

(spring force 1)K_{1}N_{1}(D_{1}+Delta)

I have a spring set(springs in parallel) on top of an object and a spring set supporting the object. The weight of the object is represented by F_{W}. The bottom springs are F_{1}and the top springs F_{2}. There is preload on the springs, represented by D_{1}& D_{2}repectively. I want to know how far the object will fall (Delta) in the given system.

I came up with this formula.

F_{W}+K_{2}N_{2}(D_{2}-delta)=K_{1}N_{1}(D_{1}+delta)

Some magic algebra and Presto:

delta=(F_{W}+K_{2}*N_{2}*D_{2}-K_{1}*N_{1}*D_{1})/(K_{1}*N_{1}+K_{2}*N_{2})

OK my problem. It doesn't seem to work. I plugged this into my handy-dandy spreadsheet and when I change the K value-keeping them both the same- it works fine. The higher the K the less the object falls. but when I change the compressed distance -keeping them both the same-, (which should, by hooks Law make the spring stiffer), does not change the distance the object moves. Please help.

Thank you

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# Supporting spring, object, top spring problem.

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