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 formInitial 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).
- The book's cover should be straight and unbent.
- The 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.
- 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. Time the object's motion at least five times.
- Determine how far the object actually travels as it rolls from one end to the other.
- Determine how much higher one end of the book was than the other, and how far it is from one end to the other.
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.
________________
I did this experiment on a desk, using Giancoli's Physics (ISBN 0-13-060620-0) as the book used to role a 5cm long solid aluminum cylinder that was 1.3cm in diameter. To prop up the book, I used a 12in. ruler that was 5mm thick. When the cylinder roled it did so in a smooth straight line.
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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.
________________
Measurements were made with a 30cm long ruler.
The distance the cylinder was roled was 28.3cm
The proped up end of the book measured 4.2cm (start)
The other end of the book measured 3.5cm. (end)
The first 5 runs
2.0625
2.15625
2.078125
2.078125
2.046875
When the book and the props were reversed 180 degrees the times recorded were:
2.046875
1.9375
1.828125
1.984375
1.96875
________
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 cyclinder rolled 2.084375 one way and 1.953125 the opposite way. the average of the two would be 2.01875. Because there are so many possible reasons for error (start, stop, etc.), I would estimate the accuracy to the .1 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.
________________
to determine whether the cylinder speeds up as it rolls down the incline, I set up the same props as in the first experiment, but instead of timing each roll one time, I timed it two times. I marked the book at 14cm and as the cylinder passed it I clicked on the timer, then as the cylinder reached the end of the book, I timed the roll again.
I repeated this process five times and my times were:
At 14cm At 28.3cm
1.3125 .75
1.265625 .59375
1.296875 .515625
1.375 .65625
1.34375 .6875
As you can see from the data, even without finding averages, the time from 14cm to 28.3cm is shorter, showing that the cylinder does speed up.
** Your intent seems clear enough, but in reporting lab results it's important to avoid any ambiguity. It appears obvious that you timed the ball from rest to the 14 cm mark, then from the 14 cm mark to the 28.3 cm mark and found that the ball travels approximately equal distances but travels through the second interval in much less time, which is a valid approach. However you should state this and in a concise manner describe how you conducted the timing.
Specifically how did you conduct your timing? Assuming you used the TIMER program, what specific events did you click on? **
You have some good answers, but you missed some things, and did not self-critique your work.
________
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?
________________
It took me 1 and a half hours.
________
You may add optional comments and/or questions in the box below.
________________
Very good work. Please see my one note and respond as indicated..
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 formInitial 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).
- The book's cover should be straight and unbent.
- The 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.
- 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. Time the object's motion at least five times.
- Determine how far the object actually travels as it rolls from one end to the other.
- Determine how much higher one end of the book was than the other, and how far it is from one end to the other.
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.
________________
I did this experiment on a desk, using Giancoli's Physics (ISBN 0-13-060620-0) as the book used to role a 5cm long solid aluminum cylinder that was 1.3cm in diameter. To prop up the book, I used a 12in. ruler that was 5mm thick. When the cylinder roled it did so in a smooth straight line.
________
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.
________________
Measurements were made with a 30cm long ruler.
The distance the cylinder was roled was 28.3cm
The proped up end of the book measured 4.2cm (start)
The other end of the book measured 3.5cm. (end)
The first 5 runs
2.0625
2.15625
2.078125
2.078125
2.046875
When the book and the props were reversed 180 degrees the times recorded were:
2.046875
1.9375
1.828125
1.984375
1.96875
________
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 cyclinder rolled 2.084375 one way and 1.953125 the opposite way. the average of the two would be 2.01875. Because there are so many possible reasons for error (start, stop, etc.), I would estimate the accuracy to the .1 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.
________________
to determine whether the cylinder speeds up as it rolls down the incline, I set up the same props as in the first experiment, but instead of timing each roll one time, I timed it two times. I marked the book at 14cm and as the cylinder passed it I clicked on the timer, then as the cylinder reached the end of the book, I timed the roll again.
I repeated this process five times and my times were:
At 14cm At 28.3cm
1.3125 .75
1.265625 .59375
1.296875 .515625
1.375 .65625
1.34375 .6875
As you can see from the data, even without finding averages, the time from 14cm to 28.3cm is shorter, showing that the cylinder does speed up.
** Your intent seems clear enough, but in reporting lab results it's important to avoid any ambiguity. It appears obvious that you timed the ball from rest to the 14 cm mark, then from the 14 cm mark to the 28.3 cm mark and found that the ball travels approximately equal distances but travels through the second interval in much less time, which is a valid approach. However you should state this and in a concise manner describe how you conducted the timing.
Specifically how did you conduct your timing? Assuming you used the TIMER program, what specific events did you click on? **
Respond by just copying this question, your responses and my comments into a text document and inserting your explanation. As my comments are set off by double asterisks **, set off your inserted comments using &&. Just submit a copy using the Submit Work form.
________
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?
________________
It took me 1 and a half hours.
________
You may add optional comments and/or questions in the box below.
________________
Very good work. Please see my one note and respond as indicated..