# Instrument and springs attached to it

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1. May 21, 2017

### Imagin_e

• Thread moved from the technical forums, so no Homework Template is shown
Hi!

I am trying to solve a textbook problem without any success. Fortunately, I found someone that solved it but there is one step that I don't get. Here is a figure showing the problem : https://ibb.co/koatCa

First, we have (I get this part since I found a similar use of it in the book):

X/b=1/|1-(ω/ωn)2|=0.15/0.10=1.5

And the thing I can't understand is how the person get the following numbers:

For ω<ωn : ω/ωn= 0.577
For ω>ωn: ω/ωn=1.291

Anyone who can explain?

Thanks!

Last edited by a moderator: May 22, 2017
2. May 26, 2017

### PF_Help_Bot

Thanks for the thread! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post? The more details the better.

3. May 27, 2017

### rude man

You don't define b but if you're using conventional symbols, b represents damping but there is no damping in this problem.
Anyway, define your symbols.

Would be nice if you could just write F = ma for this problem, then solve a simple ODE to get x(t) as a function of driving frequency and (constant) amplitude.