Dampened Harmonic Oscillation

[osprey099]

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TBR says that in dampened harmonic oscillation, you lose energy (amplitude) over time but frequency and period remains the same. I have a hard time seeing how period and frequency can remain the same because if a pendulum is progressively going to lower and lower amplitudes, shouldn't the period be decreasing and the frequency increasing?

 

[theCLE]

This can be demonstrated with a slinky. Move it so there are 2 nodes (for example). You will notice the amplitude slowly decreases once you stop moving your arm, but the period remains the same ( 2 nodes). The frequency will then remain the same because it's inversely proportional to period.


this guy creeps me out, but he provides some valid definitions.
http://www.youtube.com/watch?v=Elrcf-4cnjs

 

[NuttyEngDude]

I have a video too:
http://www.youtube.com/watch?v=SZ541Luq4nE

 

[brlin]

Another way to think about this, is that as the amplitude decreases, the velocity is also decreasing. Since both amplitude (distance wave must vibrate) and velocity (speed of vibration) are both decreasing, the time it takes to travel one vibration is roughly the same. Therefore, the frequency and period of vibration remains constant.