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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I'm sorry this is late. If I cannot have a grade for this assignment, I understand.

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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 this experiment, I used Physics by Giancoli ISBN- 0130606200, a thin highlighter, and a partially used Post-It notepad (approximately 0.5 cm thick). The highlighter rolled very smoothly, picking up speed as it rolled, and curving to the right.

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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 measurements of the book are 26.5 cm long by 21.5 cm wide. The propped end was 4.5 cm. high, and the low end was 4 cm high for both experiments.

You didn't report the time interval, which I believe you also measured using the TIMER.

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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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On average, the highlighter was moving 13.9802 cm per second.

This can't be verified without all the data, including the timing information, but it certainly seems plausible and I expect that you did this correctly.

I believe this is fairly accurate because my answer is based on measurements and how they correlate to one another. However, the timer is only as accurate as the person running it, so there could be a delay in the reaction time versus the actual 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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I set up my experiment similar to the first, but I added equally spaced intervals to click the timer. Then I compared the the times between the intervals in their order down the slope. Those times were .4531, .3984 and .2266. The time between each interval became faster, indicating that the highlighter was speeding up.

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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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45 minutes

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

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Very good, but see my note about including all your data.