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

You may enter any message or comment you wish in the box below:

________________ **

I'm attempting to work on things again. My wife has had some seizures this week so it's been trying. I appreciate your patience and understanding. I am by no means deserving of the kindness you have showed me and I can't thank you enough for working with me. I believe that the proctor would be the same as I submitted information for in the spring but I will contact the Crossroads Institute in Galax to make sure.

** ________

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.

________________ **

In my timing experiment, I used a book entitled, “Astronomy: Journey to the Cosmic Frontier” Third Edition written by John D. Fix. The ISBN for the book is 0-07-248262-1. The object used to roll down the book was a can of “Hunt’s Seasoned Tomato Sauce for Meatloaf”. The can was full and contained approximately 432g of tomato sauce. To prop up the book I used a standard slim CD jewel case as well as three standard size paperclips lined up beside each other. When the object was released, it rolled in a straight line each time and gradually speed up before reaching the end and slowing down very slightly. I believe that this slow down at the end could be caused either by a very slight bow in the book or the edge of the book being slightly thicker than the rest of the cover.

** ________

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.

________________ **

In this experiment the time it took for the can to travel from the start to off of the book is recorded in the table below. The table records each of the five experiments I conducted going from right to left and then the five experiments I conducted going from left to right.

Time Trial # Time It Took To Travel From Start To Finish Going From:

Right To Left Left To Right

1 2.328125 2.280273

2 2.335938 2.279297

3 2.311523 2.311523

4 2.319336 2.294921

5 2.303716 2.287109

The Length of the book and thus, also the distance the object traveled is 284mm. The height of the propped end of the book was 35mm while the height of the end that was not lifted was 28mm.

** ________

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.

________________ **

On average the object was traveling right to left in 2.3197276 seconds or 122.43mm/sec. The object traveled left to right in an average 2.2906246 seconds or 123.98mm/sec. I believe that the accuracy of which I calculated the average speed is within 10mm +/-. Although human error is definitely a factor in start and finish time calculations, my sample size was 5 which is slightly better than the minimum 3 allowed. Also, with the more accurate timer there will be more variation than if the timer rounded to say the nearest tenths place.

** ________

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.

________________ **

In order to determine if the object was speeding up or slowing down as it rolled down the book, I set up the book again, with it being propped-up on the left side. I had the book positioned at a slightly lower angle than before and thus it took the can longer to roll down the book but it allowed me to take more accurate time measurements. Below is a time table of the time trial, the time it took to travel from start to the center of the book and the time it took to travel from the center of the book to the end. (The center of the book was derived from taking the total book length of 284mm and dividing it by 2 thus getting 142mm):

Time Trial Time From Start To Middle Time From Middle To End

1 1.496094 1.023438

2 2.112305 1.175781

3 1.631836 1.095703

The data in my experiment supports the hypothesis that the can is speeding up as it travels down the book. This can be seen in the fact that it takes less time to travel from the center of the book to the end as it does to go from the start of the book to the center even though they represent the same distances in millimeters.

** ________

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: 

________________ **

It took me approximately 1 and 1/2 hours to complete this experiment.

** ________


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

________________ **

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