phy 201
Your 'pendulum counts in-class' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
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20090829 2300
ic_class_090826
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Pendulum - 1/2 Cycle Counts:
Length of pendulum - Wrist to tip of middle finger (19.15 cm)
Trial 1 - 137
Trial 2 - 134
Trial 3 - 135
Average - 135.33
Length of pendulum - Wrist to tip of middle finger x 2 (38.3 cm)
1 - 98
2 - 97
3 - 97
A - 97.33
Length of pendulum - Wrist to tip of middle finger x 4 (76.6 cm)
1 - 70
2 - 70
3 - 70
A - 70
Report one line per observation. Each line should consist the length of the pendulum being observed, the 1-minute count and the scale factor by which your reported length should be multiplied to get the length of the pendulum in centimeters. The three requested quantities should be separated by commas. Each line should therefore consist of three numbers, separated by commas. Don't include any words, units, or other information in any of these lines.
You may report as many lines as possible. Use the space below.
Your data report (start on the next line):
19.15 135.33 1
38.3 97.33 2
76.6 70 4
Add your description of how you made your observations. Include an explanation of how much uncertainty there was in each observation, and explain how you arrived at your uncertainty estimate.
Your explanations (start on the next line):
Clock time was measured with a clock timer (watch) which was started at the top of the extreme. To ensure the most accurate measurements of the pendulum lengths - the initial measurement (wrist to tip of middle finger) was measured as that. The second length was measuring using a needle nose plier and looping the string back to almost the middle of the center of the washer (not quite the middle because the string traveling around the pliers added length). The third length was measured this same method but using the second length to loop instead of the first length. The first pendulum was held between fingertips and the other two pendulum were help off the end of a desk with needle nose pliers and a rubberband around the handle (to reduce friction at the top of the pendulum). The 1/2 cycles were simply counted by hitting the Enter key in an Excel cell each time the pendulum reached an extreme. Uncertainty levels would be based on +/- 1/4 cycles accordingly to the pendulum - since the 1/2 cycles were counted of each pendulum. Other factors such as air resistance and friction from the string rubbing across the fingertips in the first pendulum also played a roll of uncertainty but no where near as in depth as clock time resulting from unsure counts that could be accuratly (physically) measured. The measurements may be off by +/- 2 mm due to trying to use an aluminum measuring tap to measure to lengths of not only the pendulum but of my wrist to middle finger tip.
Very good, though I'm still not sure what the third number in each line means.
&#Very good responses. Let me know if you have questions. &#