initial timing experiment

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 form

Initial Timing Experiment

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

________________ **

** ________

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.

________________ **

For my book I used Organic Chemistry 7e by McMurry with the ISBN of 9780495112587. For my object I used the small marble supplied in the physics kit. The object rolled very smoothly, and the direction was mostly in a straight line. It looked like it picked up speed.

** ________

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.

________________ **

Height of the incline =1.6 cm, measured to the tenth of a cm.

The length the ball traveled= 35.1 cm measured to the tenth of a cm.

Run 1 = 1.570 seconds

Run 2 = 1.235 seconds

Run 3 = 1.283 seconds

180 degree flip Run 1 = 1.023 seconds

Run 2 = 1.057 seconds

Run 3 = 1.098 seconds

I believe the length measurements are accurate to the tenth and the time measurements are accurate to the 0.01.

** ________

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.

________________ **

By adding up the six runs of the marble and diving 6, I determined that the average speed at which the marble was traveling was at 1.211 seconds.

** ________

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.

________________ **

I taped 2 metals bars together to use as a ramp for the marble to roll. I set the ramp on a book which made an incline of 3.5cm high. I then marked the metal bars in 4 equal sections which all measured 32.3 cm. I then ran the marble 3 times then averaged out the speed for each of the 4 sections. I got 2.35s avg for the first section, 1.27s avg for the second section, 1.11s avg for the third section, and 0.98s avg for the fourth section. By looking at these numbers, you can clearly see the object takes less and less time to cross the line of each equal section, meaning the object must be speeding up.

** ________

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: 

________________ **

45 minutes

** ________


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

________________ **

Excellent design, very well reported.