Phy 121
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' **
After releasing the ball on the pendulum the sounds get closer together than further apart.
** Your description of the rhythm of the pendulum when tilted 'forward' **
By using the diagram above to place the pendulum and ball as shown in the figure, the rhythm gets faster and the sounds are closer together.
** Your description of the process used to keep the rhythm steady and the results you observed: **
By using a dime under the front of the bracet made it level.
** Your description of what happened on the tilted surface (textbook and domino), rotating the system 45 degrees at a time: **
1st - the sounds get closer together and slows down
2nd - the sounds get closer together and the rhythm slows down
3rd - the sounds get closer together and the rhythm slows down
4th - the sounds get closer together and the rhythm slows down
** Your description of how you oriented the bracket on the tilted surface to obtain a steady rhythm: **
Place a dime under the back so that it is higher than the front. That would give you more of a constant beat against the bracket.
** Your report of 8 time intervals between release and the second 'hit': **
1st - it hit abour .983 sec on second strike
2nd - it hit about .945 sec on the second strike
3rd - it hit around 9.77 sec. on the second strike
4th - it hit around .998 sec on the second strike
5th - it hit around .999 sec on the second strike
6th - it hit around .969 sec on the second strike
7th - it hit under .899 sec on the second strike
8th - it hit around .956 sec on the second strike
I obtained these results by using a stopwatch, because my computer will not run the timer program. I moved the experiment into eight different positions to get more accurate results.
** Your report of 4 trials timing alternate hits starting with the second 'hit': **
1st - .967(2nd) 1.4(4th) 1.78(6th)
2nd - .998(2nd) 1.34(4th) 1.7(6th)
3rd - .989(2nd) 1.44(4th) 1.79(6th
4th - .991(2nd) 1.32(4th) 1.69(6th
I used a stopwatch again because I was unable to access and use the timer program. I used for different positions for the experiment.
** The length of your pendulum in cm (you might have reported length in mm; the request in your instructions might have been ambiguous): **
** Your time intervals for alternate 'hits', starting from release until the pendulum stops swinging: **
using the 1st trail the results go as follow:
2nd strike is .967 then there is .423 seconds till the fourth strike and .38 seconds until the sixth
** Your description of the pendulum's motion from release to the 2d hit: **
From the time you release the ball it gains speed and hits the fastest and harder than any other time that the ball strikes.
** Your description of the pendulum's motion from the 2d hit to 4th hit: **
Between the first and second hit the ball does not move with as much force as the first hit and it begins to slow down.
** 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 between the first and second hit differs from second to fourth is slower and not as hard as the first or the second strike.
&#Here is a partial description of the motion of a free pendulum. Some details have been left out, but this should provide an example of the sort of description requested:
For a free pendulum the pendulum starts at one extreme point, swings back through the equilibrium point (the point at which the pendulum would hang freely) and beyond this point to the opposite extreme point. It then swings back in the opposite direction, passing again through the equilibrium point to the original extreme point. An ideal pendulum will reach the original extreme point; a real pendulum will lose a little energy and won't make it quite back to the original point.
This constitutes one complete oscillation of the pendulum.
The motion of the pearl pendulum differs in some respects from the above description, and also shares some of the characteristics of this description.
How then would you describe the motion of the pearl pendulum from release to the second 'hit'? &#
&#How would you describe the motion from the 2d to the 4th 'hit' and how does it differ from the motion between release and the 2d '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: **
finally at the sixth strike the ball has slowed very considerable and is almost at a rest,
** Your conjecture as to why a clear difference occurs in some intervals vs. others: **
Because you would naturally assume that the first hit would be faster than the rest.
** What evidence is there that subsequent intervals increase, decrease or remain the same: **
I personally knew it would decrease because of the fact that the ball is slowing down.
If you set the system of as instructed, so that the rhythm remains constant, then the times would neither increase would decrease.
** What evidence is there that the time between 'hits' is independent of the amplitude of the swing? **
I think that it is for the hypothesis due to the fact that the results can change if the position of the pendulum changes.
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1hr 25 min
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Mr. Smith,
I can not get the timer program to work. I followed all the instructions and downloaded everything. I don't know what to do so for this exercise I used a stop watch. Please let me know what to do.
What specifically happened after you downloaded the program and tried to run it?
See my notes above, and please respond and as indicated.