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 did this experiment on my kitchen countertop using a textbook,birthday card,ruler,and a marble.The textbook was called Electricity Principles and Applications, ISBN number 0-020804847-4 measured 27mm thick by 287mm in length by 228mm in width, which was propped up at one end with the birthday that measured 1mm thick by 200mm in length by 150mm in width. The card was inserted under the head of the book 4mm.With the card under the head of the book to 27mm why the tail of the book remained at 26mm giving it a 1mm incline. I used a marble for the object to roll down the incline. It was a green marble that measured 15mm in diameter. The ruler was a standard 12 inch wooden ruler used to make measurements and was also used to hold the marble in place before starting its roll.

The marble rolled fairly slow but seemed ti speed up. It was somewhat difficult to get the book propped up to let the marble roll for at least 2 seconds. As stated above the prop was only 1mm thick.The marble seemed to roll smoothly but with a slight fade to the backbone of the book.

The samething seemed to happen when I rotated the the book and prop 180 degrees and tested.

I also used the timer that was supplied with the online class.

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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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All the items used measurements are stated in the previous box.The only extra meaurement that was made was I had to use 3mm of the head of the book to set the marble on to start the roll so this decreases the distence the marble will travel from 287mm to 284mm.All measurements taken are +/- 1mm except the birthday card.

The time it took to roll down the incline was measured by setting the marble at the top of the incline and holding it inplace.At the same time I mve the ruler to start the roll I also started the timer and observe to marble roll and then stop the timer when it dropped off the tail of the book. Listed below is the time data it took for the marble to roll down the incline. I took three measurements.Time was rounded to the hundredth of a second.

1. 2.01 seconds

2. 2.06 seconds

3. 2.11 seconds

I then rotated the complete setup and took three more measurements.

1. 2.20 seconds

2. 2.29 seconds

3. 2.15 seconds

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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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Refering to our average velocity equation, avg.v= 'ds/'dt we will find the avg.v

Given the times for the first three rolls we will first find the avg.time by taking the sum of the three and dividing by the three occurences

2.01 sec

2.06

+2.15=

6.26 divided by the three times 6.26/3=2.09secs

If we fill in the avg.v equation we get v=284mm/2.09sec

avg.v=135.90mm/s

Accuracy is maybe within 5mm.Tried starting and stopping at same points.Did the test more then one time, and used the same materials. Its just to many variables to this.

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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 would setup the same experment but would take a ruler to the book and and record the distance and time with a camera like in the videos I've previously watched in this class.We would then take the average rates and find the the change in velocity

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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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1 1/2 hours

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

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&#Very good work. Let me know if you have questions. &#