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initial timing experiment

PHY 121

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Initial Timing Experiment

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I thought I sent this once already. Not sure if you got it.

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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).

The book's cover should be straight and unbent.

The object should roll fairly smoothly.
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.

Using the TIMER program determine how long it takes the ball to roll from one end of the ramp to the other, when released from rest. Time the object's motion at least five times.

Determine how far the object actually travels as it rolls from one end to the other.

Determine how much higher one end of the book was than the other, and how far it is from one end to the other.
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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Items Used

Timer program

Small can of Beans and Franks 7.5 oz (full) 6.5 cm W

Physics book ISBN 978-0-321-56983-7 28cm L

Crayola Marker 17cm L 1cm W

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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 each item with a ruler which was very accurate down the cm. I measured the length of the book and the width of the can, the marker was measured length and width.

The instructions were

'State exactly what was measured, how it was measured, how accurately you believe it was measured and of course what the measurements were'

You did everything but the last; you never said what your measurements actually were. The measurements are implicit in your calculations below, so no problem in this case, but in general measurements do need to be reported explicitly.

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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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28/1.882813=14.871365 cm/s

28/1.9062514.688524 cm/s

28/2.109375=13.274074 cm/s

28/1.82313=15.38197 cm/s

28/1.898438=14.748967 cm/s

28/2.015625=13.891472 cm/s

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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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At my dining room table, I placed the Crayola marker at the top of the Physics book. I then placed the can of Beans and Franks at the top and let go. Using the Timer program I came up with the following times:

1st roll 1.882813

2nd roll 1.90625

3rd roll 2.109375

Each time it traveled 28 cm which is the length of the Physics book.

Then I reversed it by placing the marker at the other end of the book. These times were:

1st roll 1.820313

2nd roll 1.898438

3rd roll 2.015625

Each time it rolled straight.

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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:

Approximately how long did it take you to complete this experiment?

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

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

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&#Your work looks good. See my notes. Let me know if you have any questions. &#