initial timing experiment

phy201

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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A MSC Industrial Supply 2008-2009 catalog was used as the book. A Dasani 16.9oz (empty) water bottle was used as the cylinder. A pen was used as the prop for the incline. The object rolled smoothly down the book, gradually picking up speed as it traveled. It also rolled in a straight line as it made its way down the incline.

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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 time it took the bottle to roll from the top of the inclined book to the end of the book was measured. Three measurements were observed as followed.

1.98 secs

2.11 secs

1.85 secs

Then the book and prop was rotated 180 degrees and three more measurements were observed as followed:

1.81 secs

2.05 secs

2.01 secs

The measurements were taken using the timer program. The accuracy of the measurements was fair but it really depends on the person starting and stopping the timer. It could be more accurate if two people were used in the tests.

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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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The bottle was moving an average of 10.3 cm/sec. I feel that the calculated average speed was pretty accurate because none of the times deviated from each other no more than two tenths of a second and the distance stayed constant throughout the tests.

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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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I stoped the timer when the cylinder was halfway down the incline. I then took the average of the times when the bottle was halfway down the book and divided it by half the length of the book giving me the average speed for that portion of the run. I then compared this value to the average speed when the cylinder rolled down the entire incline. It was obvious that the cylinder gained speed as it traveled down the incline.

Length = 10.15 cm

Run 1 = 1.13 secs

Run2 = 1.02 secs

Run3 = 1.11 secs

Average speed = 9.3 cm/sec

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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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1hr 15mins

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

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&#Very good responses. Let me know if you have questions. &#