PHy 231
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 interval between pings against the bracket are becoming smaller.
** Your description of the rhythm of the pendulum when tilted 'forward' **
The interval lengthens until it eventually stops hitting the bracket.
** Your description of the process used to keep the rhythm steady and the results you observed: **
The bead hit the bracket eight times, with a reasonably steady rhythm. I adjusted the tilt of the bracket with a washer included in the lab kit and was able to create a level surface so that the bead barely rested on the side of the bracket.
** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **
Step 1: I began the experiment by aligning the bracket parrallel with the cover of the book lengthwise.
Step 2: I released the pendulum and observed a consistant interval.
Step 3: I rotated the pendulum approximately 45 degrees clockwise. I then observed a consistant interval.
Step 4: I repeatedly continued to rotate the pendulum and observed the following intervals in order.
Consistant interval
Increasing interval
Slowing increasing interval
Consistant inverval
Decreasing interval
Decreasing interval
Slowing decreasing interval
** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **
I would orient the bracket perpendicular to the slope of the surface.
** Your report of 8 time intervals between release and the second 'hit': **
.594
.594
.531
.516
.469
.609
.563
.547
Each interval is the amount of time it took for the bead to hit the bracket twice. They were obtained by taking the difference between the time of release and the time of the second hit. The consistan
** Your report of 4 trials timing alternate hits starting with the second 'hit': **
.578, .516, .547
.609, .453, .500
.547, .453, .547
.531, .469, .547
** The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous): **
15.3 cm.
** Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging: **
.547, .521, .516
** Your description of the pendulum's motion from release to the 2d hit: **
It is released from an extreme point and swings in an arc until it reaches its equilibrium point, which is when it hits the bracket. I am omiting in this explanation and those below the motion of the odd numbered and uncounted hits.
** Your description of the pendulum's motion from the 2d hit to 4th hit: **
The bead bounces from the point of equilibrium to a point almost as high as the initial extreme point and then reaches it point of equilibrium 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 point of reached at the extreme of the arc between the second and the fourth hit is less that the initial extreme.
extreme-equilibrium-extreme-equilibrium consists of fewer phases of motion than equilibrium-extreme-equilibrium-extreme-equilibrium. If the pendulum is set up so that the 'beats' are regular and consistent, then there is a clear ratio to the expected time intervals. What is that ratio and how nearly be your observations confirm that ratio?
** 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 point of reached at the extreme of the arc between the fourth hit and the sixth hit is less that the initial extreme, and less the the arc between the second and the fourth hit.
** Your conjecture as to why a clear difference occurs in some intervals vs. others: **
We should not expect it to be shorter, because the distance traveled in each subsequent arc between hits is decreasing; therefore, given the constant amount of force caused by gravity the decrease in distance should have a corresponing linear decrease in time.
** What evidence is there that subsequent intervals increase, decrease or remain the same: **
To decrease as explain in my above response.
** What evidence is there that the time between 'hits' is independent of the amplitude of the swing? **
This experiment provides evidence agains the determination of the length of a pendulum's swing depening solely upon the length of the string, because as the distance of the swing changed as we altered the slope of the bracket and this caused a change in the interval of time and thereby affected the length of the pendulum's swing in addition to the effect of the length of the string.
** **
1 hour and 15 minutes
** **
Very good, but even appear to have missed the point of one of the questions.
&#Please see my notes and submit a copy of this document with revisions and/or questions, and mark your insertions with &&&&. &#