# Vibrations Problem



## loudog (Aug 28, 2015)

I never took vibrations, and can't seem to find where the attached problem solution comes from. It's from the NCEES 2001 sample test.

Any advice as to where to look is appreciated. I couldn't come up with the answer from the MERM, Mark's, or Shigley (not saying they're not there).

Thanks for any help,

LP


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## P-E (Aug 28, 2015)

loudog said:


> I never took vibrations, and can't seem to find where the attached problem solution comes from. It's from the NCEES 2001 sample test.
> 
> Any advice as to where to look is appreciated. I couldn't come up with the answer from the MERM, Mark's, or Shigley (not saying they're not there).
> 
> ...


I don't know much about vibrations either. I'll check with my wife.


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## P-E (Aug 29, 2015)

Ok. Here it is:

This is a damped, free vibrations problem

General solution x(t) = e^-nt(c1 cos wt + c2 sin wt)

This w is the damped frequency, not equal to the natural frequency.

Damped frequency = ((natural frequency)^2 - n^2)^0.5

In your problem damped frequency and n = 3.3

Plug chug

Source MERM


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## loudog (Sep 1, 2015)

Nice, thanks so much Power.

I'll look into that and report back! I appreciate your effort.

LP


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