Phy 201
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 formInitial 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).
- 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 am using for the ramp is my calculus book, called “Calculus” (the ISBN number is 978-0-471-48481-3). The book is 27.5 cm long and 22.1 cm wide. I am using an 87 page sale catalog to prop the calculus book up into a ramp. The same catalog is 0.15 cm high. When the calculus book is propped to make the ramp, the top of the book is 3.2 cm from the table. The object I am using to roll down the ramp is an empty vitamin B-12 bottle. When the bottle rolls, it rolls straight down the ramp smoothly but changes direction when it hits the table. When I release the bottle at the top of the ramp, it speeds up as it goes down.
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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 time in seconds it took for the vitamin bottle to roll down my ramp, from the top of the book to the bottom of the book. I measured in cm how far the book rolled, from the top of the book to when the bottle stopped. I believe the time in seconds is measured very accurately since I used the TIMER program. The distance is measured somewhat accurately; I did not have a cm ruler so I measured in inches and then converted to cm.
Initial Timing Experiment
Time Distance
1st roll 3.125 sec 51.3 cm
2nd roll 2.921875 sec 76.6 cm
3rd roll 3.289063 sec 70.3 cm
180 Degree Turn Timing Experiment
Time Distance
1st roll 2.171875 sec 49.3 cm
2nd roll 2.054688 sec 71.5 cm
3rd roll 2.093438 sec 65.4 cm
The distance from the top of the book to the bottom of the book is 27.5 cm.
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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 average speed of the vitamin bottle as it rolled down the ramp was 10.9 cm/s. I am not sure if this is very accurate because my data for the second round of data is extremely different than the data I got for the first round. I tried the experiment a lot more than 3 times and could never get the same results as I did in the first round.
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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 could set the ramp up, with the book and the sales catalog as I did for this experiment. Then I could set up a ruler behind the ramp. Next I need to have a timer visible in the background so I can keep track of the time it takes the bottle to roll down the ramp. After the set up is complete, I need to record myself letting the vitamin bottle roll down the ramp. I can then look at the video, with the ability to pause at certain intervals, and record the position of the bottle and the time. I need to do this 3 times. After I record the three positions and corresponding time in seconds, I can then compare the rates between the first interval and second interval and between the second interval and third interval. If the rate between the second interval and third interval is greater than the rate between the first interval and second interval, then the hypothesis that the bottle rolls faster the farther it is down the ramp is correct.
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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?
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about an hour and a half
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You may add optional comments and/or questions in the box below.
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This experiment needs a bit more explanation in how to set it up and what EXACTLY to measure. I was very confused with this part specifically:
# 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.
I think these two points sound very familiar and I gets confusing about what exactly you want us to measure.
You made a reasonable interpretation of the instructions and appear to have obtained consistent measurements.
The average speed you report is consistent with your times and the reported length of the book.