Phy 201
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 sounds appear to get closer together and the bead strikes the plate less times
** Your description of the rhythm of the pendulum when tilted 'forward' **
the sounds appear to get further apart and the bead strikes the plate a few more times than when the plate is tilted back
** Your description of the process used to keep the rhythm steady and the results you observed: **
i put the triangle-shaped eraser that came in the lab kit under the front end of the bracket, tilting it back slightly.
the rhythm appeared to be constant, hitting the bracket about 5 times
** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **
with 1 domino under each of the top two corners of the textbook, I placed my pendulum in the center of the textbook making the pendulum tilt forward a bit
pulling back the bead and releasing it, the rhythm appeared to be slow and far apart
turning the pendulum counterclockwise 45 degrees, I repeated the process as before but noticed a change in the rhythm that the bead made. it appeared to be faster than test 1
every 45 degrees of rotation caused the bead's rhythm to increase with the fastest rhythm to be 180 degrees from the initial position of the pendulum
repeating the same process for the last 180 degrees of the experiment, the bead's rhythm appeared to slow down with each 45 degree turn counterclockwise
0 degree - rhythm slow far apart
-315 degrees - rhythm slow far apart
-270 degrees - rhythm slow far apart
-225 degrees - rhythm faster closer together
-180 degrees - rhythm fastest close together
-135 degrees - rhythm slowing back down close together
-90 degrees - rhythm slow far apart
-45 degrees - rhythm slow far apart
** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **
I would place the bracket horizontally across the face of the book
** Your report of 8 time intervals between release and the second 'hit': **
1 - .422
2 - .438
3 - .422
4 - .430
5 - .422
6 - .441
7 - .422
8 - .441
taking into account human error on my part for the release-click portion of the experiment, my data shows that the bead is bouncing at a constant rate for the experiment as a whole.
** Your report of 4 trials timing alternate hits starting with the second 'hit': **
.492, .590, .520, .484
.461, .504, .450
.500, .480, .500
.523, .580, .512
first off, my hand/eye coordination isn't what it used to be. the data shows that for every other 'bounce' of the bead against the bracket, the time intervals decrease in time from one another because the swinging motion is slowing down until it eventually stops.
If you set up the system so that the rhythm remains constant, the times should not vary; in fact the results you give here do not seem to indicate either a decrease or an increase in the time intervals.
** The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous): **
using the printed rulers that came with the lab kit I measured the pendulum to be :
11.5 cm
** Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging: **
.49, .54, .50
** Your description of the pendulum's motion from release to the 2d hit: **
the bead is released from the 'extreme point' following a constant, smooth curve down until it strikes the plate at which time the bead returns in the opposite direction (up) with the same smooth trajectory but with less velocity
** Your description of the pendulum's motion from the 2d hit to 4th hit: **
I believe the motions between first and second 'hits' are the same with the exception of the velocity the bead is moving
The pendulum does not start its motion from the second in the fourth 'hit' at an extreme point, so the description would not be the same. How would the description be different, and how is this related to your data?
** 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: **
each subsequent 'hit' produces less velocity for the bead (the distance the bead is from the plate diminishes with each '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: **
each subsequent 'hit' produces less velocity for the bead (the distance the bead is from the plate diminishes with each 'hit')
** Your conjecture as to why a clear difference occurs in some intervals vs. others: **
would it? I would think it would be the longest because the plate has transferred the energy from the bead back into the bead sending it back in the opposite direction
** What evidence is there that subsequent intervals increase, decrease or remain the same: **
decrease because the bead will ultimately come to rest
** What evidence is there that the time between 'hits' is independent of the amplitude of the swing? **
the longer the pendulum the longer it will swing because of the energy expended with the initial 'drop'
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1 hr 40 minutes
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Very good work, but see my one note. Submit a short note with your response to the question I opposed there.