# Prelim 5a discussion, speed of falling yoyo **URL:** \ **Category:** General Yo-Yo\ **Created:** [November 17, 2022, 10:58pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017 "2022-11-17T22:58:07Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![YoYoMa1](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/yoyoma1/32/167867_2.png) [@YoYoMa1](https://forums.yoyoexpert.com/u/YoYoMa1)\ **Post date:** [November 17, 2022, 10:58pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/1 "2022-11-17T22:58:07Z")
This is how you calculate the distance that a free-falling object is travelling. I’m sure some of you remember this formula from physics class in school. ![formula 1](https://us1.discourse-cdn.com/flex015/uploads/yoyoexpert1/original/4X/6/3/5/6358ac0f23d1439f3e5a7b5c150e6a40d5454949.jpeg) d is the distance travelled, g is the gravitational acceleration which is 9,81ms/s^2 on earth and t the time that was spent falling. This formula is perfect for our case because the time is squared. That means that if an error was added to the time to make the time smaller, then the error will be squared too. I analyzed the aerial trick he does at 11 seconds. All timestamps are referring to the time that are on the top right of the video by the way. Let me quickly explain the physics: when you toss an object up it will eventually reach its peak. Then at the peak the yoyo will simply drop as if someone held the object at that height and let go of it. It will accelerate at 9,81ms/s^2 towards the earth. So at 11:53 I chose the peak of the aerial trick he did and at 11:33 I chose the end of the free fall. Peak ![image](https://us1.discourse-cdn.com/flex015/uploads/yoyoexpert1/original/4X/6/b/3/6b3e0c14ab983dea18d3c59d8799b3e3023a6d21.jpeg) End of free fall ![image](https://us1.discourse-cdn.com/flex015/uploads/yoyoexpert1/original/4X/2/8/2/282770f5796df2939d83860dd0102a23b3a82365.jpeg) Ok now let’s plug these numbers into our formula: ![image](https://us1.discourse-cdn.com/flex015/uploads/yoyoexpert1/original/4X/6/5/c/65c3c191d17266d9edba7edf4dfb1f789f0103ef.jpeg) The yoyo could have only travelled 20cm in that time but it went from above his head to below his belt. That’s much more than 20cm ---
**Author:** ![hobby\_master](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/hobby_master/32/145533_2.png) [@hobby\_master](https://forums.yoyoexpert.com/u/hobby_master)\ **Post date:** [November 17, 2022, 11:02pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/2 "2022-11-17T23:02:15Z")
Does this account for momentum? ---
**Author:** ![YoYoMa1](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/yoyoma1/32/167867_2.png) [@YoYoMa1](https://forums.yoyoexpert.com/u/YoYoMa1)\ **Post date:** [November 17, 2022, 11:02pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/3 "2022-11-17T23:02:52Z")
I don’t know, please prove me wrong. I don’t get how the numbers are so far off. ---
**Author:** ![SR1](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/sr1/32/104603_2.png) [@SR1](https://forums.yoyoexpert.com/u/SR1)\ **Post date:** [November 17, 2022, 11:03pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/4 "2022-11-17T23:03:59Z")
I am comically horrendous at math, so I’m gonna take your word for it lmao. It did already look unnatural to my eyes, but I appreciate you “showing your work” (unlike me in Algebra - I just copied my friend’s answers and hoped I wouldn’t get dinged too bad for not showing the work 😅) Now… if only the 9/11 commission put this much effort into figuring out how the twin towers fell at near free fall speeds :thinking::thinking::thinking: ---
**Author:** ![hobby\_master](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/hobby_master/32/145533_2.png) [@hobby\_master](https://forums.yoyoexpert.com/u/hobby_master)\ **Post date:** [November 17, 2022, 11:04pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/5 "2022-11-17T23:04:47Z")
9.81m² only accounts for free falling objects. ie released from a distance not accounting for current speed of throw. Also how could you prove he isnt pulling down on the string, or tugged it back down ---
**Author:** ![ExYoyoAddict](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/exyoyoaddict/32/145064_2.png) [@ExYoyoAddict](https://forums.yoyoexpert.com/u/ExYoyoAddict)\ **Post date:** [November 17, 2022, 11:08pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/6 "2022-11-17T23:08:34Z")
There are a lot of issues with this calculation. The most glaring to me are the fact that you can’t accurately judge distance and that the yoyo isn’t necessarily in free fall. ---
**Author:** ![YoYoMa1](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/yoyoma1/32/167867_2.png) [@YoYoMa1](https://forums.yoyoexpert.com/u/YoYoMa1)\ **Post date:** [November 17, 2022, 11:19pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/8 "2022-11-17T23:19:28Z")
My thought was that the vertical speed of an object that is reaching its apex is zero. > [@hobby\_master](#): > > Also how could you prove he isnt pulling down on the string, or tugged it back down When he catches the counterweight the string that leads to the yoyo isn’t tight, it has slack so he can’t be pulling. I think I said more than I should have in that other thread. I presented it like I found definitive proof but I understand that I only applied basic middle school physics here. It’s not proof. It’s an idea that I want to discuss, I found it very intriguing to use the gravitational acceleration to judge if the time is sped up or not. But I’m sorry for having acted like I got solid proof 😅 ---
**Author:** ![Marioyo](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/marioyo/32/303068_2.png) [@Marioyo](https://forums.yoyoexpert.com/u/Marioyo)\ **Post date:** [November 17, 2022, 11:20pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/9 "2022-11-17T23:20:49Z")
![image](https://us1.discourse-cdn.com/flex015/uploads/yoyoexpert1/original/4X/e/4/9/e497a8df29d6144c64cf11c9052f3c84e6a5101e.jpeg) [![](https://us1.discourse-cdn.com/flex015/uploads/yoyoexpert1/original/4X/3/7/9/3791c805a7be93220b6694568b74a9e643c393f8.jpeg "Tom Petty - Free Fallin'") ](https://www.youtube.com/watch?v=1lWJXDG2i0A) ---
**Author:** ![MoosaK](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/moosak/32/116955_2.png) [@MoosaK](https://forums.yoyoexpert.com/u/MoosaK)\ **Post date:** [November 17, 2022, 11:22pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/10 "2022-11-17T23:22:21Z")
Ok sure the yoyos in free fall in that moment. Now you have more issues tho, how are you gauging distance here? Theres nothing we have for accurate reference ---
**Author:** ![YoYoMa1](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/yoyoma1/32/167867_2.png) [@YoYoMa1](https://forums.yoyoexpert.com/u/YoYoMa1)\ **Post date:** [November 17, 2022, 11:23pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/11 "2022-11-17T23:23:25Z")
Do you think we could use his body for reference? ---
**Author:** ![MoosaK](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/moosak/32/116955_2.png) [@MoosaK](https://forums.yoyoexpert.com/u/MoosaK)\ **Post date:** [November 17, 2022, 11:28pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/12 "2022-11-17T23:28:47Z")
No, actually i dont think so. The yoyo isnt always directly in line with his body, also hes playing so hes not always straight etc, the darkness of the bottom half of the video also obscures this. The camera angles not always straight on. You would need to be very precise to show he sped up the video if you want to show he sped it up by, say, 5% ---
**Author:** ![YoYoMa1](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/yoyoma1/32/167867_2.png) [@YoYoMa1](https://forums.yoyoexpert.com/u/YoYoMa1)\ **Post date:** [November 17, 2022, 11:34pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/13 "2022-11-17T23:34:24Z")
Yea, I thought the same. Every point you mentioned brings an error to my simplified model. My thought was that the 20cm that you get from this model are so far off that even with the errors you could see that the yoyo is falling much faster than it should. It went from over his head to his pants, that looked like way more than 20cm to me. ---
**Author:** ![MoosaK](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/moosak/32/116955_2.png) [@MoosaK](https://forums.yoyoexpert.com/u/MoosaK)\ **Post date:** [November 17, 2022, 11:41pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/14 "2022-11-17T23:41:28Z")
Theres a couple factors still missing here, first off the counterweight is taught with the yoyo and it seems as though he let go of the counterweight with a downward push. Also by the time you see the yoyo where it is in the second picture you posted, i think hes already tugged it down a bit earlier Edit: In fact he tugs down right after the peak ---
**Author:** ![ExYoyoAddict](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/exyoyoaddict/32/145064_2.png) [@ExYoyoAddict](https://forums.yoyoexpert.com/u/ExYoyoAddict)\ **Post date:** [November 17, 2022, 11:42pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/15 "2022-11-17T23:42:59Z")
I’m not sure you could consider it in freefall because of the motion of the counterweight. Also, those screenshots are from the prelim performance that judges already cleared. ---
**Author:** ![Lefski](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/lefski/32/1430_2.png) [@Lefski](https://forums.yoyoexpert.com/u/Lefski)\ **Post date:** [November 17, 2022, 11:46pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/16 "2022-11-17T23:46:01Z")
You could use the diameter of the yoyo as a rough approximation. These are the only known dimensions. Exact calculation is impossible under these conditions. ---
**Author:** ![CloudyDino](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/cloudydino/32/181747_2.png) [@CloudyDino](https://forums.yoyoexpert.com/u/CloudyDino)\ **Post date:** [November 17, 2022, 11:46pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/17 "2022-11-17T23:46:52Z")
Yeah I have to agree with @MoosaK above. I think that at 11:51, the string is still under some tension and that the counterweight (which has a non-zero velocity at that moment) could be pulling on the yoyo. Not sure how much of a difference that makes, but I don’t see a true slack in the string until the next frame at 11:48 which means he could have been tugging until then. Even in that short time, I see the yoyo move about 2-3 diameters downward which would make me think that there was some forces involved and that this is not actually freefall. ![Screen Shot 2022-11-17 at 6.32.26 PM](https://us1.discourse-cdn.com/flex015/uploads/yoyoexpert1/original/4X/1/a/5/1a5c174811c9e0a7e24961a61f0a36ad7791076a.jpeg) ![Screen Shot 2022-11-17 at 6.34.08 PM](https://us1.discourse-cdn.com/flex015/uploads/yoyoexpert1/original/4X/7/0/3/703d7c549995b37e3a4799b66b7776002b659820.jpeg) ---
**Author:** ![YoYoMa1](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/yoyoma1/32/167867_2.png) [@YoYoMa1](https://forums.yoyoexpert.com/u/YoYoMa1)\ **Post date:** [November 17, 2022, 11:49pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/18 "2022-11-17T23:49:32Z")
Yea that was my idea but if you make a small mistake then your mistake will add up. So if the yoyo fits let’s say 15 times into the distance travelled then you will have 15 times your mistake. ---
**Author:** ![Albertino](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/albertino/32/302953_2.png) [@Albertino](https://forums.yoyoexpert.com/u/Albertino)\ **Post date:** [November 18, 2022, 7:47am UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/19 "2022-11-18T07:47:48Z")
I am horrible at math but this thread is incredible, I do not if he cheated or not (from the video to me seems yes, some part of the video get slightly speed up and some not) but this whole study is crazy, hope you find your answer YoYoMa and congrats for all the research you doing! ---
**Author:** ![YoYoMa1](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/yoyoma1/32/167867_2.png) [@YoYoMa1](https://forums.yoyoexpert.com/u/YoYoMa1)\ **Post date:** [November 18, 2022, 8:10am UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/20 "2022-11-18T08:10:15Z")
Thanks😀 I don’t think I will get anywhere with my idea tho. To judge the distance I need to estimate it, but then my “proof” is just another speculation. ---
**Author:** ![jhb8426](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/jhb8426/32/631_2.png) [@jhb8426](https://forums.yoyoexpert.com/u/jhb8426)\ **Post date:** [November 18, 2022, 8:15pm UTC](https://forums.yoyoexpert.com/t/prelim-5a-discussion-speed-of-falling-yoyo/366017/21 "2022-11-18T20:15:03Z")