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:

________________

________

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.

________________

This experiment was set up on my blanket chest. A full 8oz. can of tomato sauce was used to roll across the cover of the book Physics by Giancoli, ISBN# 1-13-060620-0. The can rolled 28.5 mm down the length of the book. Another book, Knowing God by J.I. Packer, ISBN #0-8308-1650-X, was placed beneath Physics to raise the top edge to an incline of 2.3 mm from the blanket chest. The bottom edge of the physics book rested on the blanket chest. The can rolled on a straight path down the incline of the book and seemed to pick up speed as it rolled.

________

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.

________________

The length of time was measured from when the can began rolling at the top of the book until it rolled off the bottom of the book. The five measurements were as follows:

2.296875

2.0625

2.484375

2.265625

2.15625

The physics book and prop were then turned 180 degrees and the process was repeated with the following measurements:

1.53125

1.453125

1.5

1.3125

1.515625

These measurements show that the blanket was not level, which caused a discrepency in the two sets of measurements. There are many factors that may have caused the inaccuracy in measurements. One such could have been how far Knowing God was placed beneath Physics. The exact time the can rolled off the end of the book could not have been precisely caught by the timer since it was manually operated. The can may have started at a different place for each trial, rolled off center or been given an accidental nudge, any of which would have altered the accuracy and comparison.

________

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.

________________

The average speed of the first trial was 2.2530. The average speed for the second trial was 1.5. Together their average was 3.8. This is not a very accurate estimate due to the unlevel surface and the various factor which could have affected the speed of the can.

________

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.

________________

Place a ruler along the length of the inclined book. From the top of the book, mark off 8 mm, 16 mm, and 24 mm. Use a pencil for this experiment as the object to roll down then book on an incline. Click to time event at the 0mm mark, and then again at the 8 mm, 16 mm and 24 mm marks. Then, observe the time it takes for the pencil to roll each stretch of 8 mm. Repeat experiment five times. Compare the results.

Here are the results I received for each of my 5 trials:

Trial 1.

0-8mm 29.84375 .8125

8-16mm 30.48438 .640625

16-24mm 30.84375 .359375

Trial 2.

0-8mm 74.48438 .890625

8-16mm 74.85938 .375

16-24mm 75.125 .265625

Trial 3.

0-8mm 119.3594 1.03125

8-16mm 119.7031 .34375

16-24mm 119.9375 .234375

Trial 4.

0-8mm 148.2031 1.046875

8-16mm 148.5781 .375

16-24mm 148.75 .171875

Trial 5.

0-8mm 186.6563 1.375

8-16mm 187.0625 .40625

16-24mm 187.4219 .359375

This data shows that the pencil speeds up as it rolls down the incline. In each trial, the time it took to roll from 0-8 mm was longer than the time the pencil took to roll from 8-16 mm. The pencil rolled fastest from 16-24 mm in every trial. This shows that as the pencil proceed down the incline, it picks up speed. Presumably the pencil would be rolling at it’s fastest speed as it rolls off the bottom of the book.

________

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: 

________________

1 hour

________


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

________________

It was difficult to figure out how to get the book at an incline that was just high enough that the object would roll for at least 2 seconds. I kept making the incline too high and the objecty would take less than two seconds to roll, so I would make it lower and the object wouldn't roll at all.

Excellent work. You did a good job of reporting and describing yoru experiment and your results.

Please let me know if you have any questions related to this orientation assignment.

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:

________________

________

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.

________________

This experiment was set up on my blanket chest. A full 8oz. can of tomato sauce was used to roll across the cover of the book Physics by Giancoli, ISBN# 1-13-060620-0. The can rolled 28.5 mm down the length of the book. Another book, Knowing God by J.I. Packer, ISBN #0-8308-1650-X, was placed beneath Physics to raise the top edge to an incline of 2.3 mm from the blanket chest. The bottom edge of the physics book rested on the blanket chest. The can rolled on a straight path down the incline of the book and seemed to pick up speed as it rolled.

________

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.

________________

The length of time was measured from when the can began rolling at the top of the book until it rolled off the bottom of the book. The five measurements were as follows:

2.296875

2.0625

2.484375

2.265625

2.15625

The physics book and prop were then turned 180 degrees and the process was repeated with the following measurements:

1.53125

1.453125

1.5

1.3125

1.515625

These measurements show that the blanket was not level, which caused a discrepency in the two sets of measurements. There are many factors that may have caused the inaccuracy in measurements. One such could have been how far Knowing God was placed beneath Physics. The exact time the can rolled off the end of the book could not have been precisely caught by the timer since it was manually operated. The can may have started at a different place for each trial, rolled off center or been given an accidental nudge, any of which would have altered the accuracy and comparison.

________

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.

________________

The average speed of the first trial was 2.2530. The average speed for the second trial was 1.5. Together their average was 3.8. This is not a very accurate estimate due to the unlevel surface and the various factor which could have affected the speed of the can.

________

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.

________________

Place a ruler along the length of the inclined book. From the top of the book, mark off 8 mm, 16 mm, and 24 mm. Use a pencil for this experiment as the object to roll down then book on an incline. Click to time event at the 0mm mark, and then again at the 8 mm, 16 mm and 24 mm marks. Then, observe the time it takes for the pencil to roll each stretch of 8 mm. Repeat experiment five times. Compare the results.

Here are the results I received for each of my 5 trials:

Trial 1.

0-8mm 29.84375 .8125

8-16mm 30.48438 .640625

16-24mm 30.84375 .359375

Trial 2.

0-8mm 74.48438 .890625

8-16mm 74.85938 .375

16-24mm 75.125 .265625

Trial 3.

0-8mm 119.3594 1.03125

8-16mm 119.7031 .34375

16-24mm 119.9375 .234375

Trial 4.

0-8mm 148.2031 1.046875

8-16mm 148.5781 .375

16-24mm 148.75 .171875

Trial 5.

0-8mm 186.6563 1.375

8-16mm 187.0625 .40625

16-24mm 187.4219 .359375

This data shows that the pencil speeds up as it rolls down the incline. In each trial, the time it took to roll from 0-8 mm was longer than the time the pencil took to roll from 8-16 mm. The pencil rolled fastest from 16-24 mm in every trial. This shows that as the pencil proceed down the incline, it picks up speed. Presumably the pencil would be rolling at it’s fastest speed as it rolls off the bottom of the book.

________

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: 

________________

1 hour

________


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

________________

It was difficult to figure out how to get the book at an incline that was just high enough that the object would roll for at least 2 seconds. I kept making the incline too high and the objecty would take less than two seconds to roll, so I would make it lower and the object wouldn't roll at all.

Excellent work. You did a good job of reporting and describing yoru experiment and your results.

Please let me know if you have any questions related to this orientation assignment.