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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Book: The Real Mother Goose ABCs

ISBN:0-439-63372-9

Object: cap from a lipstick tube

Size of object: Diameter of opening: 2cm Length of short side: 3.8cm Long side:4cm

Props: 1 CD-ROM disk without package, 1 3.5*5 index card, and 1 football trading card, stacked on top of each other

I rolled the cap down the book on a wood dining table.

The object rolled in a straight line.

The object speed up and then slowed down before stopping.

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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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Time (up the table) Length of roll

4.36seconds 50cm

6.55seconds 62cm

5.78seconds 55cm

4.52seconds 57cm

5.88seconds 62cm

Time(down the table) Length of roll

5.78seconds 62cm

5.67seconds 62cm

4.22seconds 69cm

4.98seconds 62cm

5.16seconds 63cm

Width of book: 29cm (book was turned sideways)

Raised side of the book: 1.5cm in height

Flat side of the book: 1.1cm in height

The timer program measured the time it took for the cap to roll from the raised end of the book to where it stopped on the table. A flexible 12 inch long ruler measured the distance traveled, the width of the book, and the height of each side of the book.

The measurements with the ruler may be somewhat rough, because the ruler had to be moved and readjusted to measure the length the cap traveled.

The timer should be farely accurate because I clicked the timer as soon as the cap started rolling.

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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 distance: 60.4cm

Average time: 5.29seconds

60.4cm/5.29seconds=11.42cm/second

The estimate should be farely accurate becuase there was little delay in timing the rolls and the distances were measured carefully, but with some eye-balling of the exact lengths.

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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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You could measure off equal lengths in the path of the object and time how long it takes the object to go from one checkpoint to the next.

1 5124.25 5124.25sec at 0 inches

2 5125.063 .8125 at 6inches

3 5125.359 .296875 at 12inches

4 5125.953 .59375 at 18inches

5 5126.688 .734375 at 24inches

I used the same book, table, and cap as above and rolled the cap at an incline and measured the time it took for the cap to roll to specific points alongside a measuring tape. I measured the time every 6 inches. Between 6 and 12 inches, the object was going faster than it was going at 12 to 18 inches. The object sped up from its initial speed and then started slowing down.

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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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2 hours

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

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Excellent work. Sorry for the late posting--this experiment and the one immediately preceding it (from another student) somehow got left out when I posted.