phy121
Your 'pearl pendulum' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** Your general comment, if any: **
** Your description of the rhythm of the pendulum when tilted 'back' **
The sound sped up as the swings got smaller.
** Your description of the rhythm of the pendulum when tilted 'forward' **
It remained steady until the swing was no longer far enough to contact the bracket.
** Your description of the process used to keep the rhythm steady and the results you observed: **
Since my lab kit came with two rather large magnets, I used one of them to create an adjustable rear leg for the bracket.
** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **
Base pointed twards bottom of the book; No change in rythm noted.
After trying all 8 positions, I could not, by ear, pickup a single change in the rythm.
** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **
Any position produced the exact same rythm as far as my ears were concerned. We will say that having the face of the bracket with the pendulum attached facing the bottom edge of the book was the most accurate.
** Your report of 8 time intervals between release and the second 'hit': **
1:.484375
2:.375
3:.375
4.359
5:.438
6:.469
7:.438
8:.453
** Your report of 4 trials timing alternate hits starting with the second 'hit': **
.469, .563, .609, .563
.406, .594, .625, .579, .625
.453, .563, .594, .594, .609
.5, .563, .578, .594
** The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous): **
23mm
** Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging: **
.457, .571, .601
** Your description of the pendulum's motion from release to the 2d hit: **
The pearl moves from its extreme point to equilibrium, but striking the bracket, is sent back the direction it came, expending its energy on the bracket.
** Your description of the pendulum's motion from the 2d hit to 4th hit: **
The pearl swings from the bracket back to its extreme point (or as close as it can get) using up the energy created by striking the bracket, then stops at the extreme point, and rebuilds energy on the down swing, expending that energy on the bracket again.
** Your description of the difference in the pendulum's motion from release to the 2d 'hit', compared to the motion from the 2d 'hit' to the 4th hit: **
The swing is just shortened, due to energy loss.
** Your description of the difference in the pendulum's motion from the 2d to the 4th 'hit' compared to the motion from the 4th to 6th hit: **
The swing is just shortened due to energy loss
That is true, but the more important difference is that there are four phases to the motion between the second and fourth 'hit' and only three phases to the motion between release and the second 'hit'.
** Your conjecture as to why a clear difference occurs in some intervals vs. others: **
The pearl stops at the end of each swing, increasing the timer interval
** What evidence is there that subsequent intervals increase, decrease or remain the same: **
increase, due to the lessened height of the extreme point.
If the rhythm is constant, the decrease in the amplitude of motion has no effect on the time between 'hits'. This is not the reason for the increased time. See my previous note.
** What evidence is there that the time between 'hits' is independent of the amplitude of the swing? **
The pearl took more time to make each sucessive swing based on my information. This would tell me that striking the bracket expended energy and lenghtening the ammount of time it took for the pearl to strike the bracket again. I would say that it supports the hypothesis in the fact that shorter distances=longer swings in this this experiment.
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~1 hour
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&#Your work looks good. See my notes. Let me know if you have any questions. &#