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.

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Initial 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).

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.

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SETUP -

Ramp - the Physics textbook (ISBN: 0-13-060620-0)

Prop - The Innocent Man by John Grisham

Object – full can of tomato paste

The can rolled smoothly down the ramp in a straight line as long as it was aligned with the edge of the textbook. If not it would list to the side. It rolled equally the same from the 180 degrees facing left.

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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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Ramp – L = 28.2 cm; W = 22cm; H = 3.5 cm

Prop - H = 3.2 cm

Object – L = 8.5 cm; D = 5.4 cm or r = 2.7 cm

Area of object -

A= 2πrl + 2πr^2

= 2π * 2.7 * 8.5 + 2π 2.7^2

= 144.13 + 45.78

= 189.91 cm^2

All measurements are accurate to 1 mm and were taken using a standard cm ruler.

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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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DATA TABLE(s)–

Ramp facing right -

TRIAL DISTANCE (cm) TIME (s) SPEED (cm/s)

1 28.2 .97 29.07

2 28.2 1.03 27.37

3 28.2 1.08 26.11

Ramp facing left -

TRIAL DISTANCE (cm) TIME (s) SPEED (cm/s)

1 28.2 1.06 26.6

2 28.2 1.03 27.37

3 28.2 1.46 19.32

All measurements are accurate to 1 mm and were taken using a standard cm ruler and calculator.

To determine speed, I used speed = distance/time.

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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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To determine whether or not the object was speeding up as it rolls down the incline I would increase the angle of the ramp by adding another book or 2.

I conducted the experiment using the same materials as above however I added 2 more books of equivalent size to the Grisham novel.

I then conducted trials at each new addition of book and measured its subsequent height. Therefore, I conducted 3 trials @ 2 books + textbook and 3 trials @ 3 books + textbook. My results are below.

DATA TABLE(s) –

2 books + textbook – H = 10.2 cm

TRIAL DISTANCE (cm) TIME (s) SPEED (cm/s)

1 28.2 .67 42.09

2 28.2 .60 47

3 28.2 .70 40.29

3 books + textbook – H = 14.1 cm

TRIAL DISTANCE (cm) TIME (s) SPEED (cm/s)

1 28.2 .47 60

2 28.2 .48 58.75

3 28.2 .49 57.55

The data supports my experiment and initial hypothesis by showing an increase in speed per each 3 trials as shown in my results above.

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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: 

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1 hr.

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

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Excellent data and very well-reported. Keep up the good work.