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:
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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.
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In this experiment the book used is the Physics, 6th edition by Giancoli for the Physics 121 course. The object being used is a spool of thread. A pencil was used to prop the book up in order to allow down roll movement of the spool of thread. The spool of thread rolled smoothly nd in a straight line. Generally the spool of thread started out slow and then sped up a little as it continued its path downhill.
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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.
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Measurements:
A spool of thread was removed from the state of rest and put into motion on a small slope down a book. The time that it took from the spool of thread to get from one end, the starting line or propped-up end, to the finish line was measured and recorded in the data section below. Time was taken and recorded from the Timer program on my computer. I tried my best to time the experiment accurately.
Data:
Trial 1:
1 738.4219 738.4219
2 740.8906 2.46875
Trial 2:
1 799.1563 799.1563
2 801.6563 2.5
Trial 3:
1 819.7188 819.7188
2 822.0469 2.328125
Trial 4:
1 844.2969 844.2969
2 846.6563 2.359375
Trial 5:
1 886.5156 886.5156
2 888.8125 2.296875
Length of book and distance the cylinder travels is 28.40 cm.
The starting line and raised end of the book is 0.50 cm above the top of the table. The other end of the book and finish line is 0.00 cm from the top of the table.
After reversing the book and its prop these are the following data for the trials:
Trial 1:
1 1284.172 1284.172
2 1286.094 1.921875
Trial 2:
1 1358.172 1358.172
2 1360.563 2.390625
Trial 3:
1 1399.266 1399.266
2 1401.563 2.296875
Trial 4:
1 1487.953 1487.953
2 1489.859 1.90625
Trial 5:
1 1527.297 1527.297
2 1529.656 2.359375
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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.
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The length of the book was 13 cm long. The following are based on the calculations below. The average time it took for the spool of thread to get from one end of the book to the other for the first set of data was 2.390625 seconds/trial. The average time it took for the spool of thread to get from one end of the book to the other for the second set of data was 2.175 seconds / trial. The average speed for the first set of data was. The average speed for the second set of data was.
Calculations:
Average Time Data 1:
2.46875 seconds + 2.5 seconds + 2.328125 seconds + 2.359375 seconds + 2.296875 seconds = 11.953125 seconds / 5 trials = 2.390625 seconds/trial
Average Time Data 2:
1.921875 seconds + 2.390625 seconds + 2.296875 seconds + 1.90625 seconds + 2.359375 seconds = 10.875 seconds / 5 trials = 2.175 seconds / trial
Speed = Velocity = meters / seconds
13 cm * 1 meter/100 cm = 0.13 m
V1= 0.13 m / 2.390625 seconds = 0.054 m/s
V2= 0.13 m / 2.175 seconds = 0.060 m/s
Average speed for all trials:
0.054 m/s + 0.060 m/s = 0.114 m/s / 2 = 0.057 m/s
V1 and V2 are within + or - 0.006 m/s of each other so that means accuracy in this case is good for up to 0.01 m/s. + or - 0.006 m/s is fairly accurate though.
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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.
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One way to do this experiment in order to have actual measurements to determine if the object is speeding up as it rolls down the incline is to take the time measurements atleast twice within 1 trial. Set up the apparatus in exactly the same way. Record the time it takes for the object to reach approximately 6.50 cm and the time for it to reach 13.00 cm. Then the average speed and meter would need to be calculated and then the average velocity for the first 6.50 cm and the average velocity for the last 6.50 cm would need to be calculated.
Start Time Time Interval at 6.5 cm Time Interval at 13 cm
Trial 1:
1 3798.031 3798.031
2 3800.531 2.5
3 3801.234 .703125
Trial 2:
4 3811.922 10.6875
5 3812.859 .9375
6 3813.359 .5
Trial 3:
7 3823.625 10.26563
8 3825.594 1.96875
9 3825.953 .359375
Trial 4:
10 3830.063 4.109375
11 3830.703 .640625
12 3831.219 .515625
Trial 5:
13 3835.078 3.859375
14 3835.516 .4375
15 3836.297 .78125
Average Time Interval at 6.5 cm
2.5 seconds + .9375 seconds + 1.9687 seconds + 0.640625 seconds + 0.4375 seconds
= 6.484325 seconds / 5 trials = 1.296865 seconds
Velocity at 6.5 cm
6.5 cm * 1 m/100 cm = 0.065 m
V= m/s = 0.065 m / 1.296865 seconds = 0.050 m/s
Average Time Interval at 13 cm
0.703125 seconds + 0.5 seconds + 0.359375 + 0.515625 seconds + 0.78125 seconds
= 2.859375seconds / 5 trials = 0.571875 seconds
Velocity at 13 cm (6.5 cm)
6.5 cm * 1 m/100 cm = 0.065 m
V= m/s = 0.065 m / 0.571875 seconds = 0.11 m/s
The first 6.5 centimeters down the book are a lot slower than the second 6.5 cm to the end. For first 6.5 centimeters the velocity was 0.050 m/s and for the second 6.5 centimeters the velocity was 0.11 m/s which was a lot faster. Thus the spool of thread picks up speed the further it goes down a slope.
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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?
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This experiment took about an hour and 15 minutes to set up and complete.
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You may add optional comments and/or questions in the box below.
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Your work looks ver good. Let me know if you have any questions.