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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 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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The book I used is the Physics textbook (ISBN 0130606200). An empty 12 oz aluminum soft drink can to roll. A remote control to prop the book up. One end of the book was about 10 mm higher than the lower end. The can will roll about 280 mm down the ramp.

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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 from the time the can was released to roll down the book and was stopped and stopped the timer as well. Then I reversed the setup and repeated the experiment. I believe that I measured the times with some accuracy, as I tried to time the release and stop of each roll consistently.

Times (original)

2.875

1.9375

2.421875

2.53125

2.0625

Times (reverse setup)

1.203125

1.15625

1.125

1.109375

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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 can rolled at an average speed of 159.7 mm/sec. I got the average from averaging each time, then dividing 280 mm by the average from the times of the 10 rolls.

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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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To determine if the can was speeding as it rolled down the ramp, I let the can roll from the top and stopped it halfway down the ramp and stopped the timer as well. Then I let the can roll down the last half of the ramp and timed it. I repeated this ten times and recorded the times. I combined both times from the can rolling down both halves of the ramp, and because the combined times are greater than the original times, it means that the can has accelerated when it was not stopped halfway down the ramp.

Combined Times

1.5625

1.484375

1.4375

1.359375

1.421875

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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.

** template form

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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This looks very good. Let me know if you have any questions. &#