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Andy Ruina
Attends Cornell University
Lives in Ithaca, New York
58 followers|12,036 views
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Andy Ruina

commented on a video on YouTube.
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More on bicycle balance.  Can you balance something half-way between a bicycle and a tricycle?  This video shows that gravity, the thing that superficially makes it  hard to balance a bicycle, allows you to steer it:  https://www.youtube.com/watch?v=rNQdSfgJDNM
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Andy Ruina

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Of the various videos on the internet about this bicycle self-balance, including my own, this one is the best.  Here is another 3 minute video about our bicycle balance research, but on a different topic.  What is halfway between a bicycle and a tricycle?  Answer: something you can't steer.
https://www.youtube.com/watch?v=rNQdSfgJDNM
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+Jason Moore Jason: As best I know the Minute-Physics guy did not interview Jaap, Arendt, Jim, Jody or me. Nor even, though the film seems to have a look-alike in it, you. He did a fantastic job of studying our www sites and papers. When we started this project in 1985, Jim Papadopoulos had the idea that we could never supplant David Jones (Physics Today 1970 and 2006) in the scientifically-minded public's eye concerning the mechanics of bicycle balance. I think this video establishes our view, essentially Jim's view, as fleshed out especially by the Delft-Arend-Jody experiments and simulations, as the present state of the art. Jones was a great guy many ways, but I think the new established folk lore, as really well presented in this video, is now basically just what Jim hoped for 30 years ago as a proper replacement. Done without getting any for-the-purpose propaganda from us, that I know of.
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Andy Ruina

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Three things:
1) If you liked this video, here's a 3 minute video about another unsteerable bike:  https://www.youtube.com/watch?v=rNQdSfgJDNM
2) Destin. You have made a nearly perfect and perfectly fun video.
3) I think the word "understanding" is somewhat misused in this video.  I think you mean "are able to".  You are saying that conscious understanding of something and ability to do it are unrelated.  One can have either one without the other. Note: most of what our brain does is like that. We are fooled by those things that we watch ourselves learn, and imagining that we have conscious control. Really most things are mostly below that part of our brain. We have no real conscious understanding of most of what we can do.
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Andy Ruina

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Destin:  I think your eyes are more developed than mine.  I am sure you see something at 250K/s that I don't see.  May I suggest that at the highest frame rate you do at least one play back at about 2 frames/s?  Please.  Unfortunately I can't get YouTube to play back like that for me.    Thanks.
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Andy Ruina

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Hi Dan:  
  I woke up this morning and wondered about you.  I found some of your your nice instructional videos. A bit RIBS like somehow! The monkey video is really good.    I think I may know where is an unused high-quality microphone (I gave one to my sister because of her unfulfilled audio-production ambitions). Still interested in a good mike?
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Andy Ruina

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Too fast!  Slow it down more.  Or go frame by frame at 25K/s.   How does the needle prick turn into the circumferential crack? How does that open up and leave the balloon shaped water blob?
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You don't need to slow it down anymore to answer either of those questions. Once the needle has puncture the rubber, the weight of the water in the bottom of the balloons pulls on the rubber, causing it to tear horizontally. Not to mention, it's easier for the tear to travel along where the stress in the rubber is the same, rather than traveling down or up into areas where the rubber is stretched different amounts. The balloon shaped water blob is left simply because the rubber retracts faster than gravity can pull the water down. I don't think slowing it down more would have answered either of those, since those were, in a sense, intuitive.
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Have him in circles
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Andy Ruina

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If you want to know more about bicycle stability generally, and don't want to spend hours at it, here is the best 3 minute video on bicycle self-stability ever made: https://www.youtube.com/watch?v=oZAc5t2lkvo
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Andy Ruina

commented on a video on YouTube.
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Of the various videos on the internet about bicycle self-balance, including my own, this one is the best.  Here is another 3 minute video about our bicycle balance research, but on a different topic.  What is halfway between a bicycle and a tricycle?  Answer: something you can't steer.
https://www.youtube.com/watch?v=rNQdSfgJDNM
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Andy Ruina

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Jack Ruina Memorial on March 28, 2015 at MIT's student center.
90 minutes of memorial talks. The audio is not good, but is intelligible
if you pay attention.
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Andy Ruina

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Want to share your location with me on Google+? Turn it on here: https://plus.google.com/settings
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Andy Ruina

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The boat is too beautiful.  Can I stop by Thursday or Friday to chat with you guys?
I am still interested in the minimum-rudder-use self-stable concept.
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Welcome!
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Andy Ruina

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I think the explanation of Newton's third law  here  is great, in terms of its applicability to gravity.  But the symmetry argument invoked doesn't apply in all kinds of situations where the third law does apply.  Like the friction force between dissimilar materials. 
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Have him in circles
58 people
Ronny Eriksson's profile photo
David Smullin's profile photo
maria mma's profile photo
Sean Whitehurst's profile photo
Sam Walcott's profile photo
Ross Knepper's profile photo
Susan Mortell's profile photo
Ken Birman's profile photo
Andrea Lin's profile photo
Work
Occupation
Professor, scientist
Employment
  • Professor, scientist, present
  • USGS, Shell, Texas Instruments, Appel Farm
Places
Map of the places this user has livedMap of the places this user has livedMap of the places this user has lived
Currently
Ithaca, New York
Previously
Providence, Cambridge, Boston, Washington, Arlington, Champaign Lexington, Chevy Chase - Menlo Park, Finland, Åland, Palo Alto, Israel
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Story
Introduction
Born 1953 in Providence. Moved to Champaign IL, Alexandria VA, Arlington VA, Lexington MA, Chevy Chase MD  and Cambridge, MA. Spent a year in Isael.  Went to Brown for 3 degrees. Studied, mechanics, friction and earthquakes.  Taught at Cornell in Theoretical and Applied Mechanics since Aug 25, 1980. Maried to Saskya van Nouhuys since May 15, 1993.  Two daughters: Mieke (born 1993) & Prachi (born 2001).
Education
  • Cornell University
    present
  • Cambridge School of Weston, Brown, Sidwell Friends, Taylor Elementary, George Mason Green,
Basic Information
Gender
Male
Other names
Andrew
Apps with Google+ Sign-in
  • QWOP
It's good food. It's made with fresh vegetables. It's not authentic Mexican. But it doesn't claim to be. Whole meal with drinks is about 15 dollars.
Food: ExcellentDecor: Very GoodService: Very Good
Public - 2 years ago
reviewed 2 years ago
Now the home of Andy Ruina, Saskya van Nouhuuys, Prachi Ruina and Mieke Ruina. Kim Karlsson doesn't live here anymore. The address is also called Skedholmsvägen 17.
Public - 2 years ago
reviewed 2 years ago
2 reviews
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