initial timing experiment

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

You may enter any message or comment you wish in the box below:

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Would like to have feedback. Thanks, Joshua

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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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Book used is the Physics by Giancoli Sixth Edition. ISBN: 0130606200 284mm in length

Object used is a Pilot Precise V5 Extra Fine Rolling Ball pen 127mm in length 10mm wide

Prop was made of (3) 3.25in Nashua Floppy Disks. MF-2HD Double Sided High Density 2.0 MB Capacity

The pen consistently rolled away from its tip. It rolled smoothly and accelerated as it made progress 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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2.84375,3.046875,2.90625

2.53125,2.515625,2.484375

Seconds

In the first line of measurements the pen rolled down the book with the top of the incline to left. The pen averaged about 2.9 sec per attempt. This can be assumed to be accurate to the second.

In the second line of measurements the pen rolled down the book with the top of the incline on the left. The pen averaged 2.5 sec per attempt. This can be assumed accurate to the second.

All measurements were made by me with the timer program given by the instructor

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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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Average time = 2.9 sec. Distance = 284mm Velocity = distance/time V=284mm/2.9s V=97.9 mm/s Average velocity is estimated at 98mm/s

Using the formula listed I believe that this is the most accurate measurement that I can generate. The accuracy is made by accurate meaurment of distance and time.

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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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Using the same setup as before. Giancoli is written along the side of the book. From the top of the book to the n in Giancoli is 140 mm. I measured the time it took the pen to reach the n from the top of the book and then measured the time it took the pen to reach the bottom from the n with out stopping the pen in its travel. Because the first half of its travel is much slower than its second half then I can determine that the pen is speeding up.

20 3422.164 2.0625 1st half

21 3423.102 .9375 2nd half

26 3454.688 1.859375 1st half

27 3455.547 .859375 2nd half

29 3464.547 2.265625 1st half

30 3465.375 .828125 2nd half

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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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1.25 Hours

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

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Your work is very well done.