#$&*
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.
** Initial Timing Experiment_labelMessages **
** **
Copy this document, from this point to the end, into a word processor or text editor.
Follow the instructions, fill in your data and the results of your analysis in the given format.
Regularly save your document to your computer as you work.
When you have completed your work:
Copy the document into a text editor (e.g., Notepad; but NOT into a word processor or html editor, e.g., NOT into Word or FrontPage).
Highlight the contents of the text editor, and copy and paste those contents into the indicated box at the end of this form.
Click the Submit button and save your form confirmation.
Note: The majority of student report taking less than an hour on this experiment, though a few report significantly longer times.
Take reasonable care to get good data in this experiment. Try to do the timing as accurately as possible. Measurements of length, height, etc. should be reasonably accurate (e.g., with a meter stick or ruler you can measure to withing +- 1 millimeter, but it's not necessary to try to determine fractions of a millimeter).
In this experiment you will use the TIMER program, a hardcover book, the toy car that came in your lab materials package (or, if you do not yet have the package, 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, which is also given on the Assignments page).
The book's cover should be straight and unbent.
The toy car (or other 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. For a typical book, a stack of two or three quarters placed under one end works well.
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. Once you've got the book set up, it takes only a few seconds to do a timing, so it won't take you long to time the object's motion at least three times.
Determine how far the object travels as it rolls from its initial position (where you first click the timer) to its final position (where you click at the end of the interval). This will probably be a bit less than the length of the book, due to the length of the object itself.
Determine how much higher one end of the book was than the other, and how far it is from the supports (e.g., the stack of quarters, or whatever you used to support one end) to the end of the book which rests on the table.
Then reverse the direction of the book on the tabletop, rotating the book an its supports (e.g., the stack of quarters) 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 can of vegetables (full or empty; should be specified) or a jar (again full or empty); anything round and smooth that will upon release roll fairly slowly down the incline), 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?
your brief discussion/description/explanation:
For this experiment I used the textbook, Foundations of Sport and Exercise Psychology, Fifth Edition; by Robert S. Weinberg and Daniel Gould. ISBN-13: 978-0-7360-8323-2. My object being rolled was a marble and in order to maintain a straight-line roll the marble was placed on the crease next to the binding of the book. The marble was the same marble that was supplied by the instructor. To prop the book up I used a simple key-chain bottle opener in the shape of a dog-tag. The prop was centered on the textbook.
#$&* (note that your answer should always start in one of the blank lines preceding the #$&* mark)
In the space indicated below report your data. State exactly what was measured, how it was measured, how accurately you believe it was measured and of course what the measurements were. Try to organize your report so the reader can easily scan your data and identify any patterns or trends.
your brief discussion/description/explanation:
For this experiment 3 trials per direction of the experiment were taken. For the 1st Direction from left to right, the textbook was measured at 44.5 cm. The prop was measured at .7 cm, and the distance traveled by the object was 43 cm.
The times recorded were:
2.066406
2.136719
2.167969
Upon reversing the experiment to flow from right to left, measurments were taken again getting 44.5 cm for the textbook, .7 cm for the prop, and 43 cm for the distance traveled.
The times recorded were:
2.699219
2.167969
2.496094
#$&*
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.
your brief discussion/description/explanation:
For the first setup the three trials were added and then divided by 3 to get an average of 2.098958 sec. Next I divided the distance of 43 cm by that average time and got a speed of 20.486355 cm/sec.
For the second setup the 3 trials were added and then divided by 3 to get and average of 2.454427 sec. Next I divided the distance of 43 cm by that average time and got a speed of 17.519364 cm/sec.
I believe this data to be quite accurate. Given the accuracy of the timer and precise operation, the times are very accurate.
#$&*
How fast was the object moving at the beginning of the timed interval?
According to your previous calculation, what was its average speed during this interval?
Do you think the object, when it reached the lower end of the book, was moving at a speed greater or less than the average speed you calculated?
your brief discussion/description/explanation:
At the beginning of the trial the object was resting at a speed of 0. Starting from rest the object slowly began to roll and increased its speed as the trial continued. By the time the object reached the end of the book, it was most definitely at a speed greater than the average speed calculated.
#$&*
List the following in order, from least to greatest. Indicate 'ties': The object's initial speed, its final speed, its average speed, and the change in its speed as it rolled from one end of the book to the other.
your brief discussion/description/explanation:
The change in speed, initial speed, average speed, and final speed.
#$&*
@&
If the initial speed is zero then the only way the change in speed could be less would be if the speed didn't change, in which case the speed would remain zero and all quantities would be zero. In this case the object would not go anywhere.
So at least the change in speed is not correctly placed on your list.
*@
Devise and conduct an experiment to determine whether or not the object is speeding up as it rolls down the incline. If you have set the experiment up as indicated, it should seem pretty obvious that the object is in fact speeding up. But figure out a way to use actual measurements to support your belief.
Explain how you designed and conducted your experiment, give your data and explain how your data support your conclusions.
your brief discussion/description/explanation:
In order to prove my theory that the initial speed is slower than that of the final speed I placed a pencil at 18 cm on the traveling distance assuming that this distance would take about 1 sec to reach. I recorded the time it took to reach the 18 cm mark and got a time of 1.089844 sec. Calculating the speed from this distance and time I got a final speed of 16.516125 cm/sec. This speed obviously is much slower than the average speed of the two setups which was 19.002859 cm/sec.
#$&*
@&
Good.
*@
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?
45 mins
#$&*
You may also include optional comments and/or questions.
#$&*
*#&!
&#Good responses. See my notes and let me know if you have questions. &#
#$&*
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.
** Initial Timing Experiment_labelMessages **
** **
Copy this document, from this point to the end, into a word processor or text editor.
Follow the instructions, fill in your data and the results of your analysis in the given format.
Regularly save your document to your computer as you work.
When you have completed your work:
Copy the document into a text editor (e.g., Notepad; but NOT into a word processor or html editor, e.g., NOT into Word or FrontPage).
Highlight the contents of the text editor, and copy and paste those contents into the indicated box at the end of this form.
Click the Submit button and save your form confirmation.
Note: The majority of student report taking less than an hour on this experiment, though a few report significantly longer times.
Take reasonable care to get good data in this experiment. Try to do the timing as accurately as possible. Measurements of length, height, etc. should be reasonably accurate (e.g., with a meter stick or ruler you can measure to withing +- 1 millimeter, but it's not necessary to try to determine fractions of a millimeter).
In this experiment you will use the TIMER program, a hardcover book, the toy car that came in your lab materials package (or, if you do not yet have the package, 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, which is also given on the Assignments page).
The book's cover should be straight and unbent.
The toy car (or other 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. For a typical book, a stack of two or three quarters placed under one end works well.
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. Once you've got the book set up, it takes only a few seconds to do a timing, so it won't take you long to time the object's motion at least three times.
Determine how far the object travels as it rolls from its initial position (where you first click the timer) to its final position (where you click at the end of the interval). This will probably be a bit less than the length of the book, due to the length of the object itself.
Determine how much higher one end of the book was than the other, and how far it is from the supports (e.g., the stack of quarters, or whatever you used to support one end) to the end of the book which rests on the table.
Then reverse the direction of the book on the tabletop, rotating the book an its supports (e.g., the stack of quarters) 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 can of vegetables (full or empty; should be specified) or a jar (again full or empty); anything round and smooth that will upon release roll fairly slowly down the incline), 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?
your brief discussion/description/explanation:
For this experiment I used the textbook, Foundations of Sport and Exercise Psychology, Fifth Edition; by Robert S. Weinberg and Daniel Gould. ISBN-13: 978-0-7360-8323-2. My object being rolled was a marble and in order to maintain a straight-line roll the marble was placed on the crease next to the binding of the book. The marble was the same marble that was supplied by the instructor. To prop the book up I used a simple key-chain bottle opener in the shape of a dog-tag. The prop was centered on the textbook.
#$&* (note that your answer should always start in one of the blank lines preceding the #$&* mark)
In the space indicated below report your data. State exactly what was measured, how it was measured, how accurately you believe it was measured and of course what the measurements were. Try to organize your report so the reader can easily scan your data and identify any patterns or trends.
your brief discussion/description/explanation:
For this experiment 3 trials per direction of the experiment were taken. For the 1st Direction from left to right, the textbook was measured at 44.5 cm. The prop was measured at .7 cm, and the distance traveled by the object was 43 cm.
The times recorded were:
2.066406
2.136719
2.167969
Upon reversing the experiment to flow from right to left, measurments were taken again getting 44.5 cm for the textbook, .7 cm for the prop, and 43 cm for the distance traveled.
The times recorded were:
2.699219
2.167969
2.496094
#$&*
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.
your brief discussion/description/explanation:
For the first setup the three trials were added and then divided by 3 to get an average of 2.098958 sec. Next I divided the distance of 43 cm by that average time and got a speed of 20.486355 cm/sec.
For the second setup the 3 trials were added and then divided by 3 to get and average of 2.454427 sec. Next I divided the distance of 43 cm by that average time and got a speed of 17.519364 cm/sec.
I believe this data to be quite accurate. Given the accuracy of the timer and precise operation, the times are very accurate.
#$&*
How fast was the object moving at the beginning of the timed interval?
According to your previous calculation, what was its average speed during this interval?
Do you think the object, when it reached the lower end of the book, was moving at a speed greater or less than the average speed you calculated?
your brief discussion/description/explanation:
At the beginning of the trial the object was resting at a speed of 0. Starting from rest the object slowly began to roll and increased its speed as the trial continued. By the time the object reached the end of the book, it was most definitely at a speed greater than the average speed calculated.
#$&*
List the following in order, from least to greatest. Indicate 'ties': The object's initial speed, its final speed, its average speed, and the change in its speed as it rolled from one end of the book to the other.
your brief discussion/description/explanation:
The change in speed, initial speed, average speed, and final speed.
#$&*
@&
If the initial speed is zero then the only way the change in speed could be less would be if the speed didn't change, in which case the speed would remain zero and all quantities would be zero. In this case the object would not go anywhere.
So at least the change in speed is not correctly placed on your list.
*@
Devise and conduct an experiment to determine whether or not the object is speeding up as it rolls down the incline. If you have set the experiment up as indicated, it should seem pretty obvious that the object is in fact speeding up. But figure out a way to use actual measurements to support your belief.
Explain how you designed and conducted your experiment, give your data and explain how your data support your conclusions.
your brief discussion/description/explanation:
In order to prove my theory that the initial speed is slower than that of the final speed I placed a pencil at 18 cm on the traveling distance assuming that this distance would take about 1 sec to reach. I recorded the time it took to reach the 18 cm mark and got a time of 1.089844 sec. Calculating the speed from this distance and time I got a final speed of 16.516125 cm/sec. This speed obviously is much slower than the average speed of the two setups which was 19.002859 cm/sec.
#$&*
@&
Good.
*@
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?
45 mins
#$&*
You may also include optional comments and/or questions.
#$&*
*#&!
&#Good responses. See my notes and let me know if you have questions. &#