initial timing experiment

PHY 201

Your 'initial timing experiment' 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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Initial Timing Experiment

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In this experiment you will use the TIMER program, a hardcover book, a cylinder or some other object that will roll along the book in a relatively straight line, and a ruler or the equivalent (if you don't have one, note the RULERS link on the Assignments page).

Place the book on a flat level tabletop.  You will prop one end of the book up a little bit, so that when it is released the object will roll without your assistance, gradually speeding up, from the propped-up end to the lower end.  However don't prop the end up too much.  It should take at least two seconds for the ball to roll down the length of the book when it is released from rest.

Then reverse the direction of the book on the tabletop, rotating the book and its prop 180 degrees so that the ball will roll in exactly the opposite direction.  Repeat your measurements.

In the box below describe your setup, being as specific as possible about the book used (title, ISBN) and the object being used (e.g., a solid glass marble, a small can of tomato paste (full or empty?), a ball-point pen), and what you used to prop the object up (be as specific as possible).   Also describe how well the object rolled--did it roll smoothly, did it speed up and slow down, did it roll in a straight line or did its direction change somewhat?

Note:  Don't trust this form.  Compose your answer in Notepad or a word processor, saving it every few minutes, then copy and paste it into the box.  Power could surge, your computer could malfunction, in any of a number of ways the work you put into this form could be lost.  Compose it elsewhere and keep a copy.

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For The initial timing experiment I used a brand new cylindrical magic marker weighing approximately two ounces as the rolling object. The ramp consisted of the sixth edition of Physics by Giancoli, ISBN 0130606200. The textbook was elevated by a steel shot bean bag used for weighting down engineering plans. The object rolled very smoothly down the ramp in both directions, never changing its course. The object started rolling very slowly but gradually increased its speed as it got nearer to the end of the ramp.

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In the box below report your data.  State exactly what was measured, how it was measured, how accurately you believe it was measured and of course what the measurements were.  Try to organize your report so the reader can easily scan your data and see any patterns that might occur.

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The length of the surface of the cover of the book that was used as the ramp was measured to be 27.94cm. The height of the ramp was 1.905cm. A digital stopwatch was used to time the object. The first three times on the ramp were 1) 1.00 s, 2) 1.00 s, and 3) 1.13 s. The ramp and was rotated 180 and the second three times were 1) 1.22 s, 2) 1.18 s, and 3) 1.17 s.

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Using your data determine how fast the object was moving, on the average, as it rolled down the incline.  Estimate how accurately you believe you were able to determine the object's average speed, and give the best reasons you can for your estimate of the accuracy.

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Using the equation for average speed, average speed = distance traveled/time elapsed, the average speed for the first ramp condition was determined to be 0.2687 m/s and the average speed for the ramp condition reversed 180 was determined to be 0.2348 m/s. I don’t believe the estimations of the average speed are very accurate. The ramp surface is fairly short in length witch lead to lower times. The lower times are harder to accurately measured using a stopwatch or timing program that requires the human hand eye coordination to be consistent throughout the experiment, which they are not in my case.

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Devise and concuct an experiment to determine whether or not the object is speeding up as it rolls down the incline.  If you have set the experiment up as indicated, it should seem pretty obvious that the object is in fact speeding up.  But figure out a way to use actual measurements to support your belief.

Explain how you designed and conducted your experiment, give your data and explain how your data support your conclusions.

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For the revised experiment I used a block placed at the midpoint of the surface to stop the object. The top half of the book was traversed in two measurements of 47/100 s and 51/100 s. The bottom half of the book was traversed in two measurements of 56/100 s and 69/100 s. The measurements show that the object traverses the lower half of the ramp faster than the top half of the ramp.

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Your instructor is trying to gauge the typical time spent by students on these experiments.  Please answer the following question as accurately as you can, understanding that your answer will be used only for the stated purpose and has no bearing on your grades: 

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It took approximately 1 hour to conduct this experiment. Twenty minutes to do the experiment and the alternate experiment and 40 minutes to type it and transfer it to these boxes.

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You may add optional comments and/or questions in the box below.

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&#This looks good. Let me know if you have any questions. &#