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 rhythm gets slower and further apart as time goes on.
** Your description of the rhythm of the pendulum when tilted 'forward' **
The is more steady as time goes then it comes to a stop.
** Your description of the process used to keep the rhythm steady and the results you observed: **
I have a magnet on the top and a domino under the bracket on the ball side.
** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **
Start position facing the domino
fast then slow with a steady rhythm
Clockwise
Steady rhythm
Clockwise 90 degrees
clockwise 135 deg.
The sounds are very close togther
clockwise 180 deg.
Very slow and moves slowly with out hitting the bracket.
clockwise 225 deg.
Sounds the same as 135 degrees
clockwise 270 deg
sounds the same as 90 degrees
clockwise 315 deg.
sounds the same as 45 degrees
** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **
I would orient the bracket facing the domino's.
** Your report of 8 time intervals between release and the second 'hit': **
.594, .430, .430, .383, .320, .430, .406, .313
It looks like the the times are consistant and it is depends on how far back the ball is held.
** Your report of 4 trials timing alternate hits starting with the second 'hit': **
.414, .375, .383, .375
.352, .320, .328, .335
.445, .453, .406, .414
.305, .320, .375, .328
They mean that every other interval is aobut .350 sec apart
** The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous): **
15.5 cm
** Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging: **
.30, .38, .38
** Your description of the pendulum's motion from release to the 2d hit: **
it hit the same point about every other time.
** Your description of the pendulum's motion from the 2d hit to 4th hit: **
side left then right
** 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: **
it is on the right side
** 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: **
To me it looks like the sixth hit will hit on the right side
&#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 conjecture as to why a clear difference occurs in some intervals vs. others: **
I believe it would be like free fall and has more velocity
** What evidence is there that subsequent intervals increase, decrease or remain the same: **
decrease as the ball slows
** What evidence is there that the time between 'hits' is independent of the amplitude of the swing? **
The lenght of the string will does change the how much initial speed which can affect what happens to the different intervals.
The amplitude of the swing is the distance from the bracket to the point at which the pendulum, after swinging out, again begins swinging back--the extreme point of its motion.
Does the amplitude change?
Does the time between 'hits' change?
What therefore is your conclusion about independence and how is it connected to your answers to these question?
** **
about an hour
** **
I'm not sure you were timing alternate 'hits'; looks lik you were timing every 'hit'. From that information we can of course figure out the times between alternate 'hits'.
See my notes and please responsd as indicated.