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 time between each his gets closer and closer so the rhythm is getting faster.
** Your description of the rhythm of the pendulum when tilted 'forward' **
The time between each hit got further and further apart so the rhythm was getting faster.
** Your description of the process used to keep the rhythm steady and the results you observed: **
I used washers to get the angle of the bracket right and while the rhythm wasn't perfect it was much closer to a steady rhythm than the previous 2. I counted 17 hits.
** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **
At the starting position the pearl side of the bracket is facing the top of the book here are my results in degrees vs rhythm of hits:
0degrees,hits getting closer
45degrees,hits getting closer
90degrees,hits are evenly spaced
135degrees,hits get further apart
180degrees,hits get further apart
225degrees,hits get further apart
270degrees,hits are evenly spaced
315degrees,hits get closer together
** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **
So that the side of the bracket is parallel with the top of the book.
** Your report of 8 time intervals between release and the second 'hit': **
.781,.609,.578,.516,.563,.594,.563,.625
.828,.563,.563,.563,.547,.625,.625,.578
.797,.547,.609,.578,.531,.563,.563,.563
.813,.594,.531,.547,.594,.563,.594,.547
.734,.641,.578,.609,.531,.531,.531,.609
.75,.687,.578,.594,.562,.578,.609,.563
.719,.609,.609,.563,.578,.563,.609,.609
.781,.547,.609,.578,.547,.563,.578,.547
I think you've got really good data here. It's not exactly what was requested but it does contain the requested information.
All that was requested was the intervals between release and the second 'hit'. You appear to have also included times to the subsequent 'hit's. While it should have been reported separately, that information is useful.
** Your report of 4 trials timing alternate hits starting with the second 'hit': **
.688,1.22,1.09,1.11
.688,1.14,1.16,1.14
.781,1.13,1.09,1.17
.797,1.08,1.11,1.16
** The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous): **
32cm
** Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging: **
.739,1.14,1.11
** Your description of the pendulum's motion from release to the 2d hit: **
The pendulum is released at the top of its swing then drops to hit the bracket.
** Your description of the pendulum's motion from the 2d hit to 4th hit: **
The pendulum bounces of the bracket swings back up to the top of its swing then back down to hit 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 length of the swing of the pendulum decreases with every hit.
** 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 gets even smaller.
You gave pretty good descriptions, but did not desribe the adequately difference in the two motions. Your measurements are good, but until we have this information we can't assess just how good.
&#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 &#
&#Please respond with a copy of this question, a copy of any other part of this document you wish to include, and your response to the question. Indicate your response using the symbols *&##. As your title use the 'response title' suggested above (just copy and paste that title into the Title box of the Submit Work form); if no suggested title was given use your own title.
&#
** Your conjecture as to why a clear difference occurs in some intervals vs. others: **
The initial hit slows the pendulum down?
** What evidence is there that subsequent intervals increase, decrease or remain the same: **
The results from the timings seem to show they stay the same.
** What evidence is there that the time between 'hits' is independent of the amplitude of the swing? **
Because with each swing of the pendulum the length of the swing decreases but the time stays relatively the same.
** **
2hrs
** **
&#Good work. See my notes and let me know if you have questions. &#