The Pendulum Rocket Fallacy

[@AtomicFrontier]

Of course, another thing to consider is that "pointing very hot rocket exhaust at my fuel tanks" might not be a super safe design choice! Credits and FAQs in the description. P.S. This is my entry for the #VeritasiumContest (with the first round judged on number of views) so I'd love it if you could help me out and send a copy to a friend! Thanks!!! - James

[@Sibula]

Was a part of the contest having to be under a minute? Because adding a second at the end would've made the end less abrupt. Anyway, nice video and good luck in the contest.

[@AtomicFrontier]

@@Sibula I think the limit was one minute, but KZbin does a weird thing by adding 1 second to the video's time as displayed on the thumbnail (so on there it's exactly 1:00). I didn't want to risk it so went under.

[@Bill-lt5qf]

Not a problem if the fuel tank was a torus ;)

[@Maggi-wk4wv]

I think you have got something wrong when saying "both balls land at the same time". Let's assume the balls both have the same size. Both balls have to push away the same area of air beneath them. To do that, they require some force. In this case, it is the force created by the Weight (mass multiplied by earth gravitational acceleration). Both balls do obviously require the same force to push away the same amount of air in the same time. The problem is, they do not create the same force. The ball that is more heavy has a much higher weight and thus can create a larger force to push away the air beneath it. The ball with less weight can't create a very high force to push away the air beneath it. This means, the ball that weighs less needs more time to push away the air, thus needs longer to reach the floor.

[@ShawnMihalek]

@@Maggi-wk4wv He did ignore Air Resistance, but that's the standard when simplifying physics. I wouldn't say he's 'wrong', just that he didn't specify 'in a vacuum'.

[@shookings]

"for the love of Goddard" is one of the best puns in history

[@Lazy_Tim]

All the best with your entry James. You have some good completion.

[@AtomicFrontier]

Thanks! Yest, love seeing the other entries! The future of science comms is looking great!

[@lewismassie]

As someone who lives and breathes rockets, this will now be my go-to video to explain the Pendulum Rocket Fallacy (this is the highest honour I can bestow)

[@BeaverDaBeaver]

Sweet Goddard, this is the most potent short-form education I've ever seen.

[@jeanchen194]

This channel is probably the best thing I have stumbled upon this year.

[@andrewwmitchell]

Love seeing you out in nature in Western Australia again.

[@AnhadS]

Thanks for explaining a puzzling concept so well

[@AtomicFrontier]

Thanks! Glad you enjoyed it!

[@bwjclego]

Best video on the pendulum fallacy I've seen!

[@the18thdoctor3]

I believe I see the LV-T45 "Swivel" engine on those animated rockets... Or is it the LV-T30 "Reliant"?

[@M.Arsenault]

Reliant, because Swivel has trust vectoring.

[@RoachDogg_JR]

Ahh, here's the comments I was looking for. To the Mun, by Goddard!

[@reubengray1116]

Wasn't expecting a short video when I clicked. Very pleasantly surprised. good video, and best of luck for the competition!

[@ovikchoudhury5957]

Love the little 'the expanse' reference

[@tomsekmanis]

A really cool video! Even though I had never thought that rockets should have engines at the top (as all the modern ones don't), you managed to convince me that it could be a reasonable idea and explained why that is not the case very well and all that in a minute!

[@ramizr]

"For the love of Goddard"(love this line hehe) .....you nailed it ! Congratulations on winning!

[@mrmangoberry8394]

I know the solution, just pin the top in place, and it won’t move!

[@ragnkja]

True, but a rocket does need to move x)

[@Validole]

@@ragnkja Well, make it slide up a rod then! I mean, at that point you have a space elevator, but eh, details...

[@anonaustria9867]

This is by far the best explaination of the pendulum rocket fallacy I have ever heard

[@officialstrike]

0:30, nice cast away reference!

[@DrNEMO]

Oh wow. So much info brilliantly condensed in a 1-min video, James. Good luck with the contest! :)

[@ReliableDragon]

Fantastic video! Best of luck in the contest!

[@CaliforniaCarpenter7]

Howdy fella! Another great video. Keep up the great work!

[@richtigmann1]

This is so well set up and smooth :O

[@Carlyknarly]

Whenever I have a problem in life, just add fins. This is what I have taken away from this video. In legal trouble? Bad relationship? DUI? Just add fins!

[@nicjansen230]

Experienced this in KSP, never knew why it didn't work, just added fins and other constructions, but now I know :D

[@ravindranathhospital1362]

Congratulations on being a finalist. All the best for tomorrow 👍👍🎊🎊🎉🎉

[@krishras23]

Great video James and good luck for the contest

[@BillyKona6676]

Congrats on winning SECOND in the Veritasium contest! What an achievement.

[@paulamblard3836]

0:24 : say "this doesn't work" ; show it work at right (cut before it doesn't work) 0:44 : but why, in the rocket-pendulum, the thruster has not the same effect as your hand ? why the 2 situation are different ? (because the thruster push in the direction of the roket ; not perpendicularly to the ground. but i spend 4 minutes to find it.)

[@zotzot5]

although it does work if the rocket is noodley enough, as seen in stratzenblitz75's "Tylo in a mk2 cargo bay"

[@leotamer5]

I do not want to fly in any rocket which can be accurately described as "noodley enough".

[@VPCh.]

Does this video count as a short? I thought the dimensions had to be 9:16.

[@kelvin1316]

I hate shorts, just start getting into this and it ends 😞

[@amruthanand1330]

Good luck James!

[@starry_lis]

Oh god this explanation is so efficient I can't even

[@blandedgear9704]

This packs in more interesting information than some 10 minute videos!

[@OhhYasssh]

congratulations on winning the contest

[@JJRicks]

Whoa someone went all out on the After Effects! 3D motion tracking something and then rotoscoping yourself on top of it, great stuff!

[@jip5889]

Just came from Dereks 3D printed rocket video to this. Today is a good day.

[@timstump7293]

Awesome video...clear and concise presentation. You should write training videos for various procedures/ industries. Best of luck in you competition.

[@hazmatjunk9490]

You thought you could sneak that expanse reference past us. You where wrong.

[@thomasmuller8118]

din't really get why it does not work. That was to quick for me

[@seegurkekiller]

I knew about the fallacy and all, but damn, that was some well done dense information in a 1min video

[@natcracken]

0:53 Inyalowda don't know how the fins work da keagmang

[@myuuiii]

This is gonna be good

[@myuuiii]

it was good

[@eventyrer1872]

Its funny how ksp have already lernt me this without me knowing it

[@chedatomasz]

Another way to think: of you suspend the tanks from the engines, they will kind of work like a pendulum - they will align oposite the engines acceleration, but that acceleration will not be righted in any way.

[@harry1010]

WILSSSSOOOOOOOOOON!!!!!! holy heck the madmen actually did it!

[@ravindranathhospital1362]

Congratulations on winning the second prize. 🎉🎉🎉🎉🎊🎊🎊

[@pedrogabory]

That was really short, i had to loop it to get the full idea.

[@unvergebeneid]

That was actually a brilliant explanation of the pendulum rocket fallacy!

[@KekusMagnus]

moving the thrust in front of the center of lift and center of mass does make the rocket more stable though, just not as much as he thought

[@mjfan653]

i was so ready for a 20min video but i'll take anything

[@Appletank8]

would increased drag on the tail end stablize it?

[@kenjiokura7601]

Why aren't tractor (like Soyuz or Apollo) launch escape affected by this then? I guess they have TVC control or the COM is different?

[@TSZatoichi]

Are you talking about the Escape Tower? If so, the rockets for that are directed outwards a bit to miss the top of the capsule. en.wikipedia.org/wiki/Launch_escape_system Here's a test in action, start at about 1:10 if you don't want to watch the whole thing. kzbin.info/www/bejne/d6LIe61_qdGXibM Thanks for asking that question, I learned something new because of it.

[@kenjiokura7601]

@@TSZatoichi Yes. Thanks! But wouldn't there still be an upward force? I think I misunderstood the fallacy, it's not that the rockets are "more" unstable, it's that having engines on top doesn't make rockets naturally stable.

[@Validole]

@@kenjiokura7601 Yeah, this was the takeaway for me too. As for the launch escape system, it has a pretty decent aerodynamic stabilising element in the form of the capsule, I guess.

[@kiereluurs1243]

They are. But their point is that are not a lot options to get propulsion there.

[@lucidmoses]

Nice way to demonstrate the heart of the matter.

[@MonsieurPopu]

That was quick!

[@chieffirefigherplays]

Make a video about Mundaring Weir.

[@bankrupt3am932]

The ending was lovely

[@PBMS123]

Its imporatant to note that the rocket force must be pointing in line with the CoG

[@Dmck-zw5bv]

Like the expanse logos on the animation

[@unusedTV]

Sad that this was only one minute. Thought: Cool! A new upload! But turned out to be a short :( I understand you had to meet the contest requirements, but I hope you stick to longer form in general.

[@AtomicFrontier]

Thanks! Yup this was just for the comp. Back to longer ones next episode!

[@michaelwinter742]

I got cozy for this!

[@Abe-]

Wow that was concise and informative

[@ajs03]

Congrats on 2nd place, well deserved!

[@a__duck]

0:54 Outer planets Alliance swivel rocket lets go!!!!!

[@ragnkja]

Commenting for the algorithm :)

[@AtomicFrontier]

🚀🚀🚀

[@ragnkja]

@@AtomicFrontier 🚀🚀🚀🚀🚀

[@dima.d.]

Rewatching this made me think of Mariah Carey: "But it's just a sweet-sweet fallacy, baby. When I close my eyes, this rocket is stable. It's so deep in my papers, But it's just a sweet-sweet fallacy, baby…"

[@Cubium]

Excellent!

[@littledude2507]

yo do u still have the video of barker space camp from 2018???

[@uint16_t]

thanks for not making it a vertical video o7

[@betalars]

You have to have an upright aspect ratio in order for a video to be recognised as a short by KZbin. :P

[@AtomicFrontier]

Fair point. I'm not sure i could bring myself to do it though. I love my 16:9 aspect ratio too much

[@betalars]

@@AtomicFrontier I'll be honest, I do not know, if the shorts format is in general suitable for the type of content you are making. this being said: If you are already going the extra mile of condencing your videos down to one minute (wich ... honeetly felt somewhat forced while watching it) you should probably also go with the format so it get's picked up by the shorts algorythm. Otherwise there's really no reason to bend your content so it sticks to the 60 seconds rule.

[@Validole]

The 60 seconds was to conform to the contest rules.

[@betalars]

@@Validole yes, but one of the other roles ist a 9:16 aspect ratio. And there's no benefit to adhering to a subset of rules. ^^

[@WilliamPhoenix27]

This video is amazing :> And its creator more so!

[@charliemossop4057]

fantastic!

[@ashleywilson3814]

Hope this wins!

[@hi_im_eoin]

You should get 5k to never make that pun again

[@soundism1595]

gained 20k subs from last video damn; man is growing

[@Liguehunters]

Nice one

[@johnnypalacios4870]

Why this video a min long I undetected but always like to review knowledge, it help me understand mi studies

[@max_kl]

Nice video

[@willywonka3050]

WILSON!

[@mccvargues7792]

Aye, beltalawda

[@mrfrase3]

I think there's a joke in here somewhere about James and his rocket bias...

[@22Break]

Great content as per usual

[@kiereluurs1243]

'As per' misplaced cliche.

[@frozenjune83]

Looks like you tried to make a short. Clippy the paper clip is here to help with that.

[@Dr.Fluffles]

Algorithm bump ^_^

[@skycrossbones]

I LOVE THE EXPANSE REFERENCES!

[@nocturne7397]

I hate fucking KZbin shorts.

[@SprayNpreyT]

comment+

[@MetalheadAndNerd]

You did not explain why a rocket with engines on top cannot maneuver as you claim. (Of course it can if sideways thrust is modulated.) You did not explain why pushing a rocket from the end does not make the tip unstable as you claim. (Because it does?) This video is as useless as a bad teacher's lesson: "This is blablabla fallacy and now stop asking. Next topic."

[@FlyNAA]

Ayyy... I understand weighing what to include vs exclude in the meager 60 seconds (from my own entry) but to me the single most important fact would have been to show that the the pivot point is at the CG, (which doesn't change in pusher vs puller rocket) instead of (fallaciously) at the exhaust.

[@mranon42023]

you falied to explain the most important underlying concept here, air resistance. you could actually get any result like this... and the ball velocity on fall depends onf the density. bad video

[@Forest0119]

dislike all shorts

[@bikalimark]

Im disliking every #short video for a long time now, it's not agains you or anyone, it's just to show that the format is not welcome on this platform.

[@kipchickensout]

whqt

[@FrostyLosty]

This is the only good #shorts video on KZbin. The rest is plain nonsense.

[@peetiegonzalez1845]

Third

[@TSZatoichi]

FYI, if you need more views, try adding #shorts in to the title and tags. The KZbin Algorithm more heavily weights those video's so they show up in more peoples feeds. The Spiffing Brit did a whole video about it not to long ago, good luck.

[@AtomicFrontier]

Thanks, good idea!

[@max_kl]

This doesn't seem to have worked; it still doesn't look like a Shorts video