To those members of this forum who would like to carry out the experiments as described in the link
https://www.youtube.com/watch?v=xX14NK8GrDY and in the related posts of ours in this forum.
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Let me share with you some experimental experience of ours.
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1) Disadvantages of the experiment in PART 1 and in PART 2.
1A) Comparatively short time intervals due to g = 9.81 m/s2. These comparatively short time intervals are not easy to be measured experimentally.
1B) Comparatively high downward variable velocities due to g = 9.81 m/s2. These comparatively high downward variable velocities are not easy to be measured experimentally.
1C) Comparatively large sizes of the experimental device. The blue component's free fall initial height has to be at least 2 meters long as a minimum. Otherwise it is comparatively difficult to measure experimentally the time intervals and the downward variable velocities mentioned in the above items 1A and 1B. (The bigger the initial free fall height, the easier the experimental measurement of the related time intervals and downward velocities.)
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2) Advantages of the experiment in PART 1 and in PART 2.
2A) A comparatively small number of moving objects. These are only three in number -- the two couples blue rod-blue ball and the T-shaped blue component. (The Π-shaped black component is motionless.)
2B) A comparatively easy practical realization of the experimental device due to previous item 2A.
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3) Advantages of the experiment in PART 3.
3A) Comparatively long time intervals in the absence of g = 9.81 m/s2. These comparatively long time intervals are comparatively easy to be measured experimentally.
3B) Comparatively low horizontal constant velocities in the absence of g = 9.81 m/s2. These comparatively low horizontal constant velocities are comparatively easy to be measured experimentally.
3C) Comparatively small sizes of the experimental device.
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4) Disadvantages of the experiment in PART 3.
4A) A comparatively large number of moving objects. These are four in number -- the two couples blue rod-blue ball, the T-shaped blue component and the Π-shaped black component.
4B) A comparatively difficult practical realization of the experimental device due to previous item 4A.
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5) Taking into considerations all pros and cons of the experimental situation we (our team) tend to conclude that it is much better to focus on the experiment described in PART 3 of the video. Because longer time intervals and lower horizontal constant velocities (if compared to shorter time intervals and higher downward variable velocities) are much easier to be registered and measured experimentally.
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Looking forward to your comments.