Doing a project, need some insight to some physics things

  • #1
Jiku Araiguma
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I am doing a passion project that requires knowledge of physics I don't quite have, it mostly revolves around understanding human bodies and their interaction with velocity, impact, decibels, energy, etc. I'll be more specific later on.
 

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  • #2
davenn
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I am doing a passion project that requires knowledge of physics I don't quite have, it mostly revolves around understanding human bodies and their interaction with velocity, impact, decibels, energy, etc. I'll be more specific later on.

hi there
welcome to PF

well I guess if you would like some help, you had better be more specific now
what are you trying to achieve ?
what things about physics that you do not understand that are stopping you from achieving that goal ?


Dave
 
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  • #3
berkeman
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I am doing a passion project that requires knowledge of physics I don't quite have, it mostly revolves around understanding human bodies and their interaction with velocity, impact, decibels, energy, etc. I'll be more specific later on.
Hi Jiku, and welcome to the PF.

I understand that you are early in college, but that is not the way the PF works. We ask posters to make themselves very clear in their question in their original post (OP), so that folks can be efficient in helping them. We strive to have a very high signal-to-noise ratio here, so when you post saying that you will get around to asking your question in a later post, that wastes a lot of time for many of us who click into threads like yours.

This thread is closed. Please start a new thread with a full description of your question, including links to the reading that you have been doing so far to try to answer your question, and letting us know what you don't understand about your reading.

One of our main themes here at the PF is to help folks "learn how to learn", and being efficient in learning and asking questions is a big part of that. :smile:
 
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  • #4
berkeman
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Thanks to a very nice PM by @Jiku Araiguma this thread is re-opened. :smile:
 
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  • #5
Jiku Araiguma
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Thank you.

Now, the first question has to do with running. More specifically, how fast can a human run, or rather, how fast can the ideal human run? I know the world record for running speed is just under 10m/s, but can greater speeds be achieved?
 
  • #6
berkeman
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Thank you.

Now, the first question has to do with running. More specifically, how fast can a human run, or rather, how fast can the ideal human run? I know the world record for running speed is just under 10m/s, but can greater speeds be achieved?
So the obvious question is what have you found in your reading so far? Google is very good at answering questions like this one. Going beyond the basic Google information, you could ask how fast can a human run with basic assisting devices like spring loaded running devices, etc.
 
  • #7
Jiku Araiguma
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Actually, I mean just talking from the human body alone without any external assistance, just physiology.
This is so I have a base to work from, to make this part of the project feasible at least from a physics standpoint.
 
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  • #8
berkeman
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Now, the first question has to do with running. More specifically, how fast can a human run, or rather, how fast can the ideal human run? I know the world record for running speed is just under 10m/s, but can greater speeds be achieved?
Actually, I mean just talking from the human body alone without any external assistance, just physiology.
Fair enough. Obviously Olympic athletes and their coaches are looking at for how to increase their speed by a percent or two so that they can win the 2016 summer Olympics. What suggestions do you have? :smile:
 
  • #9
Jiku Araiguma
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Fair enough. Obviously Olympic athletes and their coaches are looking at for how to increase their speed by a percent or two so that they can win the 2016 summer Olympics. What suggestions do you have? :smile:
Well, I personally know almost nothing about professional running, but I would say that posture and pace have a lot to do with it, also the "spring in the step", breathing, the surface that is being tread, the friction between surfaces, air resistance, impact on each foot fall and how it affects the body of the runner, etc.

To be honest, this is for a science-fiction piece, and I want it to be plausible. One of the characters in the piece is a runner, and I want to know how fast it is possible for the human body to travel by running.
 
  • #10
A.T.
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Well, I personally know almost nothing about professional running, but I would say that posture and pace have a lot to do with it, also the "spring in the step", breathing, the surface that is being tread, the friction between surfaces, air resistance, impact on each foot fall and how it affects the body of the runner, etc.
There are also limits of the muscles, and how fast they can swing the legs back and forth. Do a search, there are old threads on this.
 
  • #11
Jiku Araiguma
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There are also limits of the muscles, and how fast they can swing the legs back and forth. Do a search, there are old threads on this.
I'm sorry, I have other questions, too. I just felt I would make one thread for all of my questions.

Well, my next question goes into the realm of scifi. How fast could an upright bipedal running machine go?What would it have to look like to go that fast?
 
  • #12
houlahound
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Biochemistry separates top athletes not physics.
 
  • #13
Jiku Araiguma
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Biochemistry separates top athletes not physics.
Yeah, I guess you're right. Still, that's only the first question I have, and I have no answers yet. I just want to know how fast.
 
  • #14
Jiku Araiguma
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Let me pose a new question, taking away the physical endurance issues, bodily wear and mental inhibitions, how fast could the mechanics of the ideal human body be pushed to go?
 
  • #15
houlahound
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The difference in world record times is a function of how many decimal places you can accurately measure.
My guess the difference between successive records is on average getting smaller, I guess this only....so get the data and do a convergent series estimate or a simple extrapolation.

My hypothesis is the series is convergent, common sense here, and the limit is not much higher than current speeds.
 
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  • #16
Jiku Araiguma
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By my previous investigations, the physical limit was 15m/s, while the world record was 9.8 or so m/s, but I think that can be pushed to 23-25 m/s at maximum without sustaining damage. I want to know if, in a hypothetical scenario, a machine free of endurance issues and physical wear with the same structure and mass could top that limit at 40 m/s or higher.
 
  • #17
houlahound
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If you are talking about a machine built like a human than I don't believe control technology is that good yet.
 
  • #18
houlahound
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Can you plot a graph of world records V time?
 
  • #19
Jiku Araiguma
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I said previously my questions reach into sci-fi territory. I'm not asking if it exists yet, I'm asking if the structure is capable of running 40m/s.
 
  • #20
houlahound
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Well in SCI FICTION yes, in fact a human can run faster than light speed.
 
  • #22
houlahound
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g1.png
 
  • #23
houlahound
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g2.png
 
  • #24
Jiku Araiguma
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Thank you. An unrelated question entirely, why can't I get these kind of results from Google?
 
  • #26
Jiku Araiguma
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I guess I've been asking the wrong questions...

Alright, new question, how fast can an upright bipedal mechanism be made to run, what would it look like, and how big would it be?
 
  • #27
billy_joule
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. I want to know if, in a hypothetical scenario, a machine free of endurance issues and physical wear with the same structure and mass could top that limit at 40 m/s or higher.

Bar the speed of light, there isn't an upper limit.
It's an engineering challenge, machines aren't limited by biology like humans are. Pick a number out of thin air and magic up the relevant engineering technology to match.
 
  • #28
houlahound
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I disagree, the op is not constrained by reality.
 
  • #29
Jiku Araiguma
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It would probably have long, thin limbs, built like wings maybe. Let's say that the target speed is 100 m/s, and the "machine" is 6 meters tall, with the sole purpose of speed. What would you say it looks like?
 
  • #30
Jiku Araiguma
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Which is more aerodynamic, sharp edges or curves?
 
  • #31
GTOM
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I have a related question, realistically, how much acceleration could a human body provide? (Needed for dodge bullet equation.)
 
  • #32
Drakkith
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Which is more aerodynamic, sharp edges or curves?

You probably want curved surfaces, as you can shape them to minimize various types of turbulence, vortices, etc. Curved surfaces also withstand debris impacts better than a sharp edge does.

I have a related question, realistically, how much acceleration could a human body provide? (Needed for dodge bullet equation.)

Your question is a bit vague, but an olympic sprinter's acceleration for the first 10 meters of a 100 meter race is around 3 m/s2. The acceleration of a hand or a foot would be greater than that.
 
  • #33
GTOM
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You probably want curved surfaces, as you can shape them to minimize various types of turbulence, vortices, etc. Curved surfaces also withstand debris impacts better than a sharp edge does.



Your question is a bit vague, but an olympic sprinter's acceleration for the first 10 meters of a 100 meter race is around 3 m/s2. The acceleration of a hand or a foot would be greater than that.
Thanks, although i wonder. If humán body cant produce more than 10 m/s2 how can it jump? Or perpendicular to a surface is a better case for gaining momentum?
 
  • #34
Drakkith
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Thanks, although i wonder. If humán body cant produce more than 10 m/s2 how can it jump? Or perpendicular to a surface is a better case for gaining momentum?

Jumping is not running. For one, you can use both legs at the same time when jumping, whereas in running only one leg provides acceleration at a time. Also, peak acceleration is probably larger than 3 m/s2 when the runner initially starts running. I'm not sure how much larger though.
 
  • #35
Jiku Araiguma
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Now, I need some thoughts on punch/impact physics. How many ways are there to produce 4000N of force with a single punch? How fast would a normal fist be going? How big/small would a fist have to be to cause damage at that force? How much damage would be caused?
 

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