Phy 121
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' **
When I released the pearl, the sounds get closer together the longer the pearl hits the bracket. The rhythm got faster.
** Your description of the rhythm of the pendulum when tilted 'forward' **
The rhythm remained steady and constant. When I released the pearl it would strike the bracket in about the same amount of seconds each time.
** Your description of the process used to keep the rhythm steady and the results you observed: **
When my bracket was on a level table the pearl did not remain steady, the rhythm kept getting faster. In order to get the rhythm steady I had to tilt the bracket forward a little bit, until the rhythm became steady. It would remain steady until the very end, in which the rhythm would get a little bit faster. The pendulum hit the bracket nine times.
** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **
I placed my physics book face up and then put dominos on each corner of the book, horizontally, so there was a total of 4 dominos on the book. Then I placed the bracket with the pendulum facing the Physics part of the book. I would then pull the pendulum up and release it and record what the sound sounded like. Then I would rotate the pendulum 45 degrees each time until the bracket was in the position from which I started. From the starting position the sounds stayed relatively constant. The first 45 degree rotation sounded closer together. When it was rotated to 90 degrees the sounds sounded further apart. When it was rotated to 135 degrees it sounded closer together. When it was rotated to 180 degrees the sound was relatively constant. When it was rotated to 225 degrees the sound was closer together. When it was rotated 270 degrees the sound was further apart. When it was rotated 315 degrees the sound was closer together.
** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **
I would orient the bracket by holding it forward a little bit, because I found holding it forward a little obtains the most regular beats.
** Your report of 8 time intervals between release and the second 'hit': **
.422
.281
.297
.312
.375
.375
.359
.531
These numbers were obtained by using the Timer Program. These numbers represent the time intervals between the pendulum hitting the bracket.
** Your report of 4 trials timing alternate hits starting with the second 'hit': **
.562, .906, .953, 1.312
.797, .797, .844, .953
.656, .766, .844, .75
.672, .734, .906, 1
My results were obtained by using the Timer Program. These number represent the time intervals between every two hits of the pendulum on the bracket.
** The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous): **
14 cm
** Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging: **
0.73, 0.81, my pendulum did not hit the sixth time.
** Your description of the pendulum's motion from release to the 2d hit: **
about 3 seconds
** Your description of the pendulum's motion from the 2d hit to 4th hit: **
about 4 seconds. It differs because with motion we clicked the button as soon as we released the pendulum
** 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: **
About 5 seconds. It differs because the motion between the second hit and fourth hit is faster, because the pendulum is starting to become to rest.
** 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: **
About 6 seconds. My pendulum didn't hit the bracket enough to get a sixth hit.
** Your conjecture as to why a clear difference occurs in some intervals vs. others: **
We would expect it to be shorter, because it has faster momentum.
** What evidence is there that subsequent intervals increase, decrease or remain the same: **
We would expect the time intervals to decrease, because the pendulums momentum is getting slower.
** What evidence is there that the time between 'hits' is independent of the amplitude of the swing? **
The length of the pendulum doesn't only depend on its lenth. How far it will swing depends on several different factors. For example how the pendulum is positioned, and how it is released.
** **
2 hours
** **
Your data look good. Be sure to review the following:
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