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 becomes faster and closer together because of the reduce distance between the bracket and the pearl.
** Your description of the rhythm of the pendulum when tilted 'forward' **
the sounds further apart and the pearl slowes down because the distance from bracket to the pearl is greater.
** Your description of the process used to keep the rhythm steady and the results you observed: **
with the bracket level there is a steady rhythm the distance i pull the pearl back makes a differnce in the number of time the pearl hits the bracket.
** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **
the was slower when point in the down direction and faster when the pendulum is rotated 180 degrees toward the top of the book
** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **
the sound is the most regular when 90 degrees from the lower position
** Your report of 8 time intervals between release and the second 'hit': **
7.468,7.882,
100.625,100.960
131.664,132.070
194.875,195.257
258.546,259.273
344.195,344.679
366.828,367.234
386.851,387.367
all the times were within .330seconds to .420seconds except when the string broke.
You should report lengths of the intervals, not their beginning and ending points (though this is a valid interpretation of the word 'interval').
The TIMER reports three columns, the second being clock times and the third being the intervals between the clock times.
** Your report of 4 trials timing alternate hits starting with the second 'hit': **
13.843,14.046
8.546,9.289
7.617, no fourth bounce
79.195,80.531
the time intervals were different because i was not as accurate counting the hits and clicking the mouse. it was very hard to distugish the hits at these intervals
** The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous): **
80mm to the end of the pearl.
** Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging: **
the average between release and second hit was .455 seconds
.760 seconds was the average between the second and fourth hits. i did not have any sixth hit so i was unable to get a measurement this could have been becuase of the string i was using.
** Your description of the pendulum's motion from release to the 2d hit: **
the motion is in an arc because of radius of the string
** Your description of the pendulum's motion from the 2d hit to 4th hit: **
the first hit slows the pearl down making the distances less for the cycle of the second hit.
** 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 motion is much shorter because the arc is smaller.
&#A full cycle of a free pendulum is from extreme point to equilibrium to opposite extreme point then back to equilibrium and finally back to (almost) the original extreme point.
The pearl pendulum is released from an 'extreme point' and strikes the bracket at its equilibrium point, so it doesn't get to the opposite extreme point.
Thus the period of the pendulum can be divided into four parts. From the steadiness of the rhythm we have good evidence that the motion between 'hits' takes the same time independent of the amplitude of the motion (the rhythm remains constant while the amplitude of the motion decreases). Theoretically each of the four parts of the cycle, as described above, takes the same time. Assuming this to be true, we can speak of the quarter-cycle from an extreme point to equilibrium or from equilibrium to an extreme point.
Through how many quarter-cycles does the pendulum move between release and the second 'hit'?
Through how many quarter-cycles does it move between the second and the fourth 'hit'?
What therefore should be the ratio of the time interval from 2d to 4th 'hit', to the interval from release to the 2d 'hit'?
How does this ratio compare with the results you just reported?
Does this constitute evidence for or against the theoretical hypothesis that the quarter-cycles all require the same time?
Suggested response title: description of motion of pearl pendulum &#
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** 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 hits are shorter there is less area in between hits.
** Your conjecture as to why a clear difference occurs in some intervals vs. others: **
we would not. the first time interval would be the longest and the last would be the shortest
** What evidence is there that subsequent intervals increase, decrease or remain the same: **
they would decrease
** What evidence is there that the time between 'hits' is independent of the amplitude of the swing? **
the lenght of the string determinds how far the pendulum can be pulled back and how many cycles it can go
** **
2 hours
** **
See my note on what constitutes a report of a time interval. Nothing wrong with your interpretation but that's not the interpretation we will apply to the term 'time interval'. The time interval does run from an initial clock time to a final clock time, but usually what we need to see is `dt.
Also see my note related to the description of interval from release to 2d 'hit', and interval between alternate subsequent 'hits'. Note that you are assuming a pendulum oriented so that the rhythm is constant.