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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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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I use the folliwng book,Carpentry and Building Construction,ISBN 0-07-822702-X. I used the steele ball found in the lab kit as my smooth object. I propped the book with a a knife sharpner. The ball rolled down the book very smoothly. The ball speeded up as it progressed down the book. The ball changed direction as it rolled.

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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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I measured the length of the book which was 28.5 mm. I also measured the higher end of the book with the knife sharpner under it, which was 4.5 mm and the lower end of the book was 3.5 mm.

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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 first three times were:

• 1.640625

• 1.8125

• 1.46875

The average was the time of the first run 1.640625.

The second three times when I reversed the prop 180 degrees the times were:

1.3125

1.265625

1.328125

The average was 1.3021.

The accuraccy was within a .001 of a second.

If the accuracy of the timer was within .001 second, it is unlikely that any of your times between clicks in the first experiment would have been the same. Only certain times are possible with the program, and these times are very roughly .01 second apart. So the timer cannot be more accurate than that.

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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 the same experiment up as describe above but measured the slope of the ramp which indicated that the ball had to be speeding up as it made its way down the ramp.

I use the folliwng book,Carpentry and Building Construction,ISBN 0-07-822702-X. I used the steele ball found in the lab kit as my smooth object. I propped the book with a a knife sharpner. The ball rolled down the book very smoothly. The ball speeded up as it progressed down the book. The ball changed direction as it rolled.

I measured the length of the book which was 28.5 mm. I also measured the higher end of the book with the knife sharpner under it, which was 4.5 mm and the lower end of the book was 3.5 mm.

The times were:

1.5

1.875

1.265625

The slope of the run was one mm diffence between the high and low end of the prop and the time increased with each run. The average time was 1.546875.

This does not test whether the ball was speeding up or slowing down. It might be obvious that it is speeding up, but you need to back that up with data, not just perception.

What measurements could you make to show that the ball is speeding up?

Please respond by submitting a copy of this question and your answer (and/or questions if you have them).

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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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33 minutes

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

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Looks good overall, but please answer the question I posed above.