Photo Contest - Simple Harmonic Motion (5/2-5/8)

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Discussion Overview

The discussion revolves around a photo contest themed on simple harmonic motion, specifically focusing on the submission of animated GIFs that depict back-and-forth motion. Participants seek clarification on the requirements for what constitutes acceptable motion for the contest entries.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant questions whether the motion depicted must strictly be harmonic, suggesting that oscillatory motion can occur without being harmonic, such as a tennis ball bouncing between walls.
  • Another participant clarifies that while the motion does not have to be strictly sinusoidal, it should resemble simple harmonic motion and not exhibit characteristics of non-harmonic motions like "square wave" motion.
  • A participant expresses their initial experience with the contest and raises a question about the behavior of the animated GIF after closing the browser.

Areas of Agreement / Disagreement

There is no consensus on the exact definition of acceptable motion for the contest, as participants have differing interpretations of what qualifies as simple harmonic motion versus other types of oscillatory motion.

Contextual Notes

Participants discuss the nuances of motion types, indicating that definitions may vary and that certain assumptions about motion characteristics are not universally agreed upon.

ZapperZ
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Simple Harmonic Motion

A few weeks ago, we inaugurated the use of animated GIF as part of our contest theme. It went quite well, so I'm bringing it back again. This time, we have a specific theme for your animated GIF. Your photo must show something that moves back and forth repeatedly, just like a simple harmonic motion.

Your animated GIF does not have to show a substantial time cycle. One or two cycles should be sufficient, unless you think that more cycles will make it convincing that your subject is undergoing this repeated motion.

As always, please be mindful of the size of your animated GIF file if you are uploading it to PF.

Contest Rules:

1. Any digital photo or digitally-scanned photo relevant to the theme will be accepted within the contest period. In case there's a gray area, or you're not sure if the picture is suitable, check with me first.

2. Size limitations: Your photo is only limited to the file size limitation set by PhysicsForums. However, your may want to consider reducing the size of your photo if the file size exceeds 1 Mb. If your file is being hosted elsewhere, I will have to see how it is being displayed here, and I may ask you to resize and resubmit if it causes problems.

3. Upload your photos to any of the photo servers such as imageshack or photobucket. Then post it the relevant contest thread and link your picture using the img command. PM me if you do not know how. Alternatively, you may simply upload your image file to PF, and then have the full image displayed in your post.

4. Only ONE picture per member per contest. Once a picture is posted, it cannot be changed other than a total withdrawal by that member from that week's photo contest. Exceptions will be made for modification to comply with the rules, such as resizing.

5. At the end of the contest period, I will open a poll and every PF member can vote for the picture they like best.

6. Note that in case we have a large number of entries, I will do the polling in more than one thread. If that's the case, you can vote in each of the polling threads. The photos will be assigned in the polling threads in the order they were submitted.

7. The photo of the subject must be something that you took directly, not via in intermediary medium, and not taken by someone else. Unless otherwise noted, a photo of another photo, painting, print, etc. does not qualify.

8. You can use a picture only once. Once it is used in a contest, it cannot be reused in another contest.

9. Please post only pictures meant for submission in this thread. Photos not meant for submission must not be posted in the contest thread. Posting of more than one photos by a member may result in an automatic disqualification from the week's contest.

Zz.
 
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Request for clarification: An object that moves back and forth repeatedly executes simple oscillatory motion which is not necessarily harmonic, e.g. a tennis ball bouncing between walls in the absence of gravity. Must the motion be harmonic, i.e. describable by a sinusoidal function if one were to model it?
 
kuruman said:
Request for clarification: An object that moves back and forth repeatedly executes simple oscillatory motion which is not necessarily harmonic, e.g. a tennis ball bouncing between walls in the absence of gravity. Must the motion be harmonic, i.e. describable by a sinusoidal function if one were to model it?

It doesn't have to be exactly a SHM, but it should resembles one. For example, the needle of a metronome goes back and forth, which qualifies. A ball bouncing between walls in the absence of gravity does not, because it doesn't slow down after it passes the center between the walls.

Strict sinusoidal motion is not required, but it should not be a "square wave" motion either.

Zz.
 
I get it, thanks.
 
My first attempt at one of these and a learning experience.
On edit: Does this thing keep swinging after I close my browser? o_O

Oscillatory_5.gif
 
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mickey plant.gif

Zz.
 
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Final day to submit your photo for this contest.

Zz.
 
Playground.gif
 
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