PHY 121
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.
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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:
I placed a book on the table with one domino underneath one end of the book so that the car will roll across the book and take around two seconds, the timer program was used to measure the time it takes for the car to travel across the book, the height of the book was measured on each end and also the height the book is from the table was measured, the book was then rotated 180 degrees and the same measurements were taken, my physics book was used and the car rolled smoothly
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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:
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the time it takes to roll off the book in one direction was 1.919 seconds
The time it takes in the other direction was 1.981 seconds
The height of the book on the lower side was 3.8 cm
The height of the book on the higher side was 4.8 cm
The book was 1 cm off the table
Length of the book was 28 cm
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:
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to find average speed = distance/ time so for the first recorded time was 28cm / 1.919 seconds = 14.59 cm/sec
for the car moving in the other direction distance/time would be
28cm/1.981 seconds = 14.13 cm/sec
I believe I was fairly accurate at recording the time because when the experiment was conducted for the second time the times recorded were very similar only differing in .4 cm/sec
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:
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The object was not moving at the beginning of the timed interval so its initial speed was 0 cm/sec
When the object reached the lower end of the book it was moving at a greaer the average speed because the object increase speed as it moved down the inclined book
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 object's initial speed, its average speed, and the change in its speed as it rolled from one end of the book to the other, its final speed
The object started at zero and picked up speed as it moved across the book have a final speed higher than its average speed calculated
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:
to test whether the object is speeding up as it rolls down the incline find a longer incline to roll the car down and using the TIMER program record the start time, time it takes for car to reach the middle of the incline, and time it takes the car to reach the end of the incline by doing this you can see that the car is moving faster from the middle to the end of the incline rather than form the beginning to the middle of the incline
set up long incline using a short ironing board whose length is 76 cm
initial time = 0 sec
middle of the board time = .936 seconds
end of the board time= .358
middle of the board length = 38 cm
so average speed from initial to middle would be 38cm/.936 seconds= 40.59 cm/sec
and average speed from middle to final would be 38cm/.358 seconds= 106.14 cm/ sec
the speed from the middle to final position of the ironing board was more than double the speed of the initial to middle average speed so this proves that as the car rolls down an incline it is increasing speed
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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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1 hour
I believe you did quite well here. However:
&#You have inserted your answers after, rather than before, the #$&* marks. In order to quickly sort your answers from the rest of the document I need the #$&* mark at the end, not the beginning of each answer. In order to give your document the review it deserves, I'm going to have to ask you to either move the line containing each #$&* to just after your inserted answer, or move your answer to just before the #$&* marks. Simply take a few minutes to do this with a copy of this document, and resubmit. Thanks. &#