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| http://weelookang.blogspot.sg/2014/05/tracker-cheryltan-student-video-frisbee.html physics of Frisbee motion this model suggests the Frisbee motion is a non-uniform acceleration motion in both x and y direction. https://www.dropbox.com/s/azhjb2q1vbhfc5a/Cheryltantracker_5model.trz vx = 7.0 m/s vy = 5.05 m/s fx = -2.804E0*t^2+7.713E0*t-7.861E0 fy = 3.977E-1*t-4.819 author of video: Cheryltan author of model: lookang |
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| http://weelookang.blogspot.sg/2014/05/tracker-cheryltan-student-video-frisbee.html physics of Frisbee motion this model suggests the Frisbee motion is a non-uniform acceleration motion in both x and y direction. https://www.dropbox.com/s/azhjb2q1vbhfc5a/Cheryltantracker_5model.trz vx = 7.0 m/s vy = 5.05 m/s fx = -2.804E0*t^2+7.713E0*t-7.861E0 fy = 3.977E-1*t-4.819 author of video: Cheryltan author of model: lookang |
Mentoring
* I cannot open my .trz file even though I dragged it into tracker, it says it cannot be loaded. What should i do now?
weelookang
i think you fix it already
Introduction:
I threw my frisbee at a big angle of attack such that it is flying at a high gradient, before falling back.
weelookang
in addition, i would use the actual tracker screen shot to illustrate, adds realism to your discussion.
weelookang
nice idea to discuss the phases. even better if you can discuss the model to represent the motion as in my trz file
https://www.dropbox.com/s/azhjb2q1vbhfc5a/Cheryltantracker_5model.trz
Phases
|
Time
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A to B (Maximum vertical displacement)
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0-1.17s
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B to B1 (Maximum horizontal displacement)
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1.17-1.92s
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B1 to C (Rest)
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1.92-2.50s
|
Questions:
I do not understand why my acceleration values are all negative although I have already set the axes and right is the positive direction.
weelookang
the negative ax suggests the acceleration in the x direction is pointing to the left, so the motion is being slowed down in x direction, which make sense.
if ax is positive, that will mean the Frisbee will speed up in + x direction.
Should I obtain the acceleration values from the acceleration graphs themselves or from the velocity graphs? I am not sure because my acceleration graphs are quite haphazard.
weelookang
i got the results for ax and ay by analysing the following graphs and using the Analyse Curve Fits.
the results suggests the following:
ax = -2.804t^2+ 7.813t-7.861 (looks like a parabola so i use parabola fit)
ay = 0.3977t-4.819 (looks like a straight line to me)
I don’t quite understand why my vertical acceleration graph is so constant. Shouldn’t there be some kind of decreasing acceleration when it is reaching point B?
weelookang
actually most free-fall object the ay = -9.81, constant value
the Frisbee data suggests the Frisbee is experiencing also a constant value of about -4.819.
what is interesting to note is the ax is actually a parabola power t^2, which is unusual, the video evidence suggests the motion is actually non-uniform acceleration in both x and y direction
finally, if you can describe the motion using model (equations) like i have, you would be more like scientists!
can you try?
Thank you so much!!!!!
weelookang
enjoy!
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