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course Phy 241
10/24 8
Acceleration vs. Ramp SlopeUsing the TIMER program, time a ball down the steel ramp when the ramp is supported by a single domino lying flat. Do five trials with this setup.
Report the median time, the distance the ball traveled from rest in this time, and the resulting acceleration.
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2.9sec, 31cm, a = approx 7.3722cm/s^2
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Report the rise and run between two points of the ramp and the resulting slope.
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2cm/30.5cm = approx .0656
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Repeat with the domino lying on its long edge, so that the rise is equal to the width of the domino. Do five trials with this setup.
Report the median time, the distance the ball traveled from rest in this time, and the resulting acceleration.
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1.35sec, 31cm, a = approx 34.0192cm/s^2
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Report the rise and run between two points of the ramp and the resulting slope.
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3.5cm/30cm = approx .1167
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Based on these two setups, at what rate does the acceleration of the ball appear to change with respect to ramp slope?
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26.647cm/s^2 per .0511 increase in slope
Good. Now simply divide to get about 500 cm/s^2 per unit of ramp slope.
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Now time the toy car down the wood ramp, using two different slopes. Be sure the ramp is straight. Suggestion: Use your textbook to help. Support it at one end with something reasonably rigid, whose thickness you can measure with good accuracy (for example a couple of CD or DVD cases would be a good choice, using one for the first setup, and both for the second). Using one hand hold the wood piece flat against the book, release the car with another hand, and operate the TIMER with your third hand. If you don't have three hands, adapt the suggestions accordingly. You might also find it helpful to use the steel ramp to press the wood ramp against the book.
For the first slope:
Report the median time, the distance the ball traveled from rest in this time, and the resulting acceleration.
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.785sec, 30cm, a = approx 97.367cm/s^2
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Report the rise and run between two points of the ramp and the resulting slope.
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4.25cm, 29.5cm, slope = approx .1441
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For the second slope:
Report the median time, the distance the ball traveled from rest in this time, and the resulting acceleration.
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.55sec, 30cm, a = 198.3471cm/s^2
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Report the rise and run between two points of the ramp and the resulting slope.
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7cm, 29.25cm slope = .2393
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Based on these two setups, at what rate does the acceleration of the ball appear to change with respect to ramp slope?
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Approx 101cm/s^2 per .0952 increase in slope
again, divide the two and you'll have a good result
????I did not have wood from class so I had to use note book??? not a problem
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Is acceleration independent of position and velocity?
You were asked previously to design an experiment to test whether acceleration is independent of position and velocity, on a ramp with constant incline.
Do a 30-minute preliminary run, using the TIMER. Just take whatever data you can in 15 or 20 minutes, and give a brief report of your setup, your data and your results. Try to be as accurate as possible within the 15-20 minute time constraint.
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I tried during my experiment several different approaches to seeing testing the idea that accel was independent of position and velocity. I tried giving a greater velocity at beginning of ramp, I placed ball at different places on the ramp, and I changed the distance that the ball had to travel. All this aside accel stayed fairly constant (what little variation I did have was probably due to errors I made in my timing or measurements) while traveling down the ramp with constant slope. This is probably due to the fact that the force acting on the ball is the x component of weight vector which for such a short dist.(ramp was approx 30cm) varies very little. With this force acting on the ball being fairly constant and accel being change in velocity divided by change in time, whether I changed position or velocity accel will stay fairly the same.
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Nice work. You almost got those average rates of change of acceleration with respect to ramp slope; just needed to divide your quantities to get a single quantity for the average rates.
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