How Does Astro The Astronaut Check His Weight ?

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Offline neilep

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How Does Astro The Astronaut Check His Weight ?
« on: 27/09/2007 20:14:47 »
Dearest Space Dwelling Life Forms,

Here's a piccy of Astro !!

[attachment=1075]

Can ewe guess what he does for a living ?....that's right ! he's a banjo player !! (oh and part time astronaut!)

Astro has been in space for a good couple of months so how does he weigh himself ?...is it possible ?



« Last Edit: 27/09/2007 20:19:48 by neilep »
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Offline syhprum

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How Does Astro The Astronaut Check His Weight ?
« Reply #1 on: 27/09/2007 21:41:42 »
The only ways I can think to do it would be with the aid of a centrifuge or some acceleration device like a bungee cord and a velocity indicator
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Offline neilep

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How Does Astro The Astronaut Check His Weight ?
« Reply #2 on: 27/09/2007 21:50:18 »
The only ways I can think to do it would be with the aid of a centrifuge or some acceleration device like a bungee cord and a velocity indicator

THANK EWE SYHPRUM !!..LOL...ewe have me thinking of Astro bouncing around perpetually whilst attached to a bungee cord !!

I assume all kinds of medical data is collected but was wondering if taking weight was in fact possible !......maybe there is a way to calculate weight loss but not the actual weight of the person.
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Offline Karen W.

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How Does Astro The Astronaut Check His Weight ?
« Reply #3 on: 27/09/2007 22:14:59 »
would standing on his head on the ceiling work! LOL! Maybe pressure against the roof when he hits it! LOL .. I don't know I am guessing ceiling scale !LOL

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Offline JP

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How Does Astro The Astronaut Check His Weight ?
« Reply #4 on: 27/09/2007 22:39:38 »
Weight (on earth) is just the force exerted by Astro when he's standing on the earth.  It's given by F=mg at the earth's surface.  "g" is a measure of the strength of gravity (gravitational acceleration) at the earth's surface, and "m" is Astro's mass.

In space, assuming he's in "zero-gravity" so you can take g to be 0.  Therefore F=m*0=0.  So he has zero weight in space.

I'm assuming you want to know how much weight he would have on earth.  To get that, you need to figure out his mass (m).  The easiest I can think of off the top of my head would be to have him sit on a big spring (or his spaceship's ejector seat!), then launch him from it (basically replace Syphrum's bungee cord with a spring).  His energy after launching from the spring depends on his mass (which you want to find) and his speed (which you'll have to measure).  This has to equal his energy before launching from the spring (which is easy to calculate).  By doing a little math, you can figure out his mass. 

Once you know his mass, you just have to multiply it by "g" to figure out his earth weight.

--You could also spin the spaceship around really fast, and he'd "stick" to the wall with some force.  If you know how fast it was spinning, and how much force he exerted on the wall, you could calculate his mass that way, too.

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Offline Karen W.

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How Does Astro The Astronaut Check His Weight ?
« Reply #5 on: 27/09/2007 22:46:21 »
I am all for spinning the ship around and slapping him up against the wall!LOL

That sounds like it might be like watching a fly get pushed by a very fast wind factor smoosh up against the window! LOL..

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Offline Karen W.

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How Does Astro The Astronaut Check His Weight ?
« Reply #6 on: 27/09/2007 22:47:23 »
Although Playing in the ejector seat may also be fun! Like a catapult!

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Offline Ben Aldhouse

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How Does Astro The Astronaut Check His Weight ?
« Reply #7 on: 27/09/2007 22:54:50 »
How about giving him one of those jet packs like they had in Moonraker? The amount of fuel he uses to do various manoeuvres will be proportional to the number of pies he has eaten.

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Offline Karen W.

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How Does Astro The Astronaut Check His Weight ?
« Reply #8 on: 27/09/2007 23:39:44 »
HEE HEE.. That sounds good!

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another_someone

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How Does Astro The Astronaut Check His Weight ?
« Reply #9 on: 28/09/2007 01:26:39 »
I think jpetruccelli is just about there.

As I understand it (I may be wrong), they calculate his mass (not his weight) but setting up some sort of resonance system with a spring of some kind - the resonant frequency of the system would depend on the elasticity of the spring (a known value) and the mass (the unknown value).

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paul.fr

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How Does Astro The Astronaut Check His Weight ?
« Reply #10 on: 28/09/2007 12:02:40 »
personally, i don't see why an astronaught would need to have their weight checked, whilst in space. Unless, it's miss astro, and she wonders if her bum looks big in said spacesuit.

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Offline Karen W.

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How Does Astro The Astronaut Check His Weight ?
« Reply #11 on: 28/09/2007 12:53:22 »
I would think weight in a space ship could be crittical when calculating certain things for load and oxygen and well perhaps things that might effect the weight coming back aren't weights important when calculating coordinates and speed of travel etc  during a space flight? I thought there was need for extreme accuracy with the weight in a craft and that they need things to maintain or not exceed certain capacity for calculations, But Don't mind me I am a television nerd.. It was just things I watched on tv, I don't have the exact reasons why or know for sure if I am even close on this!

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Offline lightarrow

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How Does Astro The Astronaut Check His Weight ?
« Reply #12 on: 28/09/2007 12:53:22 »
Another way is to put a shield of known mass on him and shoot a bullet on it (known mass and speed); then you measure the speed acquired by Astro and from momentum conservation you get Astro's mass.

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Offline Karen W.

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How Does Astro The Astronaut Check His Weight ?
« Reply #13 on: 28/09/2007 12:58:27 »
What does the bullet do Alberto? wouldn't it move real slow??

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another_someone

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How Does Astro The Astronaut Check His Weight ?
« Reply #14 on: 28/09/2007 18:25:32 »
personally, i don't see why an astronaught would need to have their weight checked, whilst in space. Unless, it's miss astro, and she wonders if her bum looks big in said spacesuit.

In general, I think there are a wide range of biometric measurements that are undertaken to understand the effects, particularly the health effects, that the environment is having on the astronauts.

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Offline lightarrow

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How Does Astro The Astronaut Check His Weight ?
« Reply #15 on: 28/09/2007 18:59:19 »
What does the bullet do Alberto? wouldn't it move real slow??
It depends on how big is the bullet  [;)]
Seriously, I wrote "bullet" but of course it could be a big iron ball or anything else.

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Offline Karen W.

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How Does Astro The Astronaut Check His Weight ?
« Reply #16 on: 29/09/2007 03:51:50 »
OH Ok! So if it were heavier and bigger would it move faster then if it were smaller and lighter?

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Offline lightarrow

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How Does Astro The Astronaut Check His Weight ?
« Reply #17 on: 29/09/2007 08:10:39 »
OH Ok! So if it were heavier and bigger would it move faster then if it were smaller and lighter?
The significant parametre is "momentum" P = m*v where m = bullet's mass and v = bullet's velocity. With a given mass M of Astro, his speed depends only on the bullet's momentum p; said V = Astro's velocity:

V = p/M = m*v/M

So, the greater bullet's speed v or its mass m or both, the greter Astro's speed V. If he is very heavy, that is M very big, p must be greater to make a significant Astro's speed V.

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another_someone

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How Does Astro The Astronaut Check His Weight ?
« Reply #18 on: 29/09/2007 14:11:47 »
Another way is to put a shield of known mass on him and shoot a bullet on it (known mass and speed); then you measure the speed acquired by Astro and from momentum conservation you get Astro's mass.

Actually, would it not be safer and simpler for Astro to shoot the bullet, and then measure the recoil.

Ofcourse, one problem with this (and to some extent with most of the other dynamic mass measurement schemes) is to take account of the shock absorption properties of the human body - how much of the shock will be absorbed and converted into heat or chemical processes?

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Offline Bored chemist

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How Does Astro The Astronaut Check His Weight ?
« Reply #19 on: 29/09/2007 16:50:01 »
The energy of the reaction might be lost as heat but the momentum would be strictly conserved.
You could tie him to a known mass with a rope and set the 2 in orbit around their common centre ov gravity. The didtance from the weight to the centre of the spinning rope would be a measure of his mass.
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Offline syhprum

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How Does Astro The Astronaut Check His Weight ?
« Reply #20 on: 29/09/2007 17:08:53 »
This had occurred to me as well also with any centrifuge type system there is the question of C of G to be considered.
Probably the best system would be to land him, weigh him, and then pick him up again.
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Offline lightarrow

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How Does Astro The Astronaut Check His Weight ?
« Reply #21 on: 29/09/2007 19:51:40 »
Another way is to put a shield of known mass on him and shoot a bullet on it (known mass and speed); then you measure the speed acquired by Astro and from momentum conservation you get Astro's mass.

Actually, would it not be safer and simpler for Astro to shoot the bullet, and then measure the recoil.

Ah, yes, certainly, but do all astronauts have guns licence?  [:)]

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Offline Karen W.

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How Does Astro The Astronaut Check His Weight ?
« Reply #22 on: 29/09/2007 20:16:00 »
What does the bullet do Alberto? wouldn't it move real slow??
It depends on how big is the bullet  [;)]
Seriously, I wrote "bullet" but of course it could be a big iron ball or anything else.
OH Ok! So if it were heavier and bigger would it move faster then if it were smaller and lighter?
The significant parametre is "momentum" P = m*v where m = bullet's mass and v = bullet's velocity. With a given mass M of Astro, his speed depends only on the bullet's momentum p; said V = Astro's velocity:

V = p/M = m*v/M

So, the greater bullet's speed v or its mass m or both, the greter Astro's speed V. If he is very heavy, that is M very big, p must be greater to make a significant Astro's speed V.
OH Ok! So if it were heavier and bigger would it move faster then if it were smaller and lighter?
The significant parametre is "momentum" P = m*v where m = bullet's mass and v = bullet's velocity. With a given mass M of Astro, his speed depends only on the bullet's momentum p; said V = Astro's velocity:

So by the force size and speed by which he is propelled is going to determine his weight??? I may still be confused when the mathmatics came into it! LOL Sorry Alberto..

Another way is to put a shield of known mass on him and shoot a bullet on it (known mass and speed); then you measure the speed acquired by Astro and from momentum conservation you get Astro's mass.

Actually, would it not be safer and simpler for Astro to shoot the bullet, and then measure the recoil.

Ah, yes, certainly, but do all astronauts have guns licence?  [:)]

V = p/M = m*v/M

So, the greater bullet's speed v or its mass m or both, the greter Astro's speed V. If he is very heavy, that is M very big, p must be greater to make a significant Astro's speed V.


LOL LOL!

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Offline JohnM

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How Does Astro The Astronaut Check His Weight ?
« Reply #23 on: 15/05/2008 03:19:22 »
Wow there are some very interesting answers in this discussion, I think my favorite would have to be shooting our astronaut and determining his mass from his momentum. Why I couldn't think of anything possibly going wrong firing projectiles in our pressurized space ship [;D].

Although these methods would all work, the safety issues might be a concern.
I think 'another_someone' had it with his resonance system, the natural frequency at which a system vibrates is equal to the square root of the spring stiffness divided by the total mass or f=√(k/m). Where k is the spring stiffness and is defined as the force required to deflect the spring a given unit of length. So we can find this easily by pushing our spring with a known force and measuring its deflection. So we can find our astronauts mass by measuring how quickly he/she bounces up and down. Pretty simple actually.

As to why you want to know their mass there are a number of reasons, mainly ensuring they're still healthy. As there is little to no gravity in space, the muscles in our body are not required to work very hard to move things around. A prolonged time in space can cause muscular atrophy, a degenerative process of the muscle tissue through lack of use, this is commonly seen in coma patients. Basically if you spend to long in space doing nothing you might not have the strength to stand up when you get back to earth.
     

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Offline syhprum

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How Does Astro The Astronaut Check His Weight ?
« Reply #24 on: 15/05/2008 11:56:43 »
I often wonder if the Americans took guns with when they went to the moon, I find it hard to imagine them going anywhere without.
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Offline Soul Surfer

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How Does Astro The Astronaut Check His Weight ?
« Reply #25 on: 15/05/2008 17:30:16 »
He has a specially designed scale with a weight on a rope and a spring. He  straps this to himself and moves into the centre of his spaceccraft and releases the weight which accelerates away from him and pushes him backwards  eventually the weight reaches the end of the string and he and the weight stop with a jolt and the scales by masuring the time it took to reach the end of the string and the strength of the spring and mass of the weight can calculate the astronaut's weight.
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Offline Make it Lady

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How Does Astro The Astronaut Check His Weight ?
« Reply #26 on: 15/05/2008 21:47:08 »
Astro would have to keep himself toned in space especially if he is spending a long time up there. I guess he would need to keep track of his body mass to check on his muscle deterioration.
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Offline Make it Lady

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How Does Astro The Astronaut Check His Weight ?
« Reply #27 on: 15/05/2008 22:04:00 »
Try this out. It shows the oscillating seat that Astro has to sit on every morning....oh! good vibrations.

www.usatoday.com/tech/columnist/aprilholladay/2005-02-04-wonderquest_x.htm
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Offline turnipsock

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How Does Astro The Astronaut Check His Weight ?
« Reply #28 on: 15/05/2008 22:40:53 »
Don't they just use a big Inertia Balance?

Quote from: somewhere
Description: The inertia balance is designed for use in a laboratory experiment in which mass is quantitatively measured independent of the earth's gravitational force. This same method is used in determining the mass of an object under weightless conditions in space flights.
The apparatus consists of two small platforms connected by two horizontal, nonsagging, spring-steel blades. A cylinder with a shoulder on which it can rest in a hole in the platform and a hook by which it can be suspended are included. This cylinder may be used as an object of unknown mass.
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Offline LeeE

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How Does Astro The Astronaut Check His Weight ?
« Reply #29 on: 16/05/2008 00:50:26 »
Heh - mass is a concept that everyone knows about but it's inertia that everyone actually knows.  'Weight' is just a distraction that only occurs when you've got two bodies, which admittedly is what applies to most people.

You could use an ordinary set of bathroom scales to measure the 'weight' of astro.  What a set of bathroom scales does isn't really measure a weight but apply a force that is calibrated to the Earth's gravity.

So stick astro on the scales and then accelerate the scales (including astro) at one Earth 'g' to just read off his 'weight'.
...And its claws are as big as cups, and for some reason it's got a tremendous fear of stamps! And Mrs Doyle was telling me it's got magnets on its tail, so if you're made out of metal it can attach itself to you! And instead of a mouth it's got four arses!

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Offline turnipsock

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How Does Astro The Astronaut Check His Weight ?
« Reply #30 on: 16/05/2008 01:02:17 »

So stick astro on the scales and then accelerate the scales (including astro) at one Earth 'g' to just read off his 'weight'.


doh! I wish I had thought of that. Wouldn't that affect his orbit though?
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Offline LeeE

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« Reply #31 on: 16/05/2008 14:29:36 »
Erm... yes, it would, although the period of time that astro needs to be accelerated isn't a factor so it could be very small, resulting in a very small change of velocity.

But if we assume this is all done inside a space vehicle, the net change will be zero, at least once he bounces off the wall.

Alternatively, he could be accelerated and then deccelerated.
...And its claws are as big as cups, and for some reason it's got a tremendous fear of stamps! And Mrs Doyle was telling me it's got magnets on its tail, so if you're made out of metal it can attach itself to you! And instead of a mouth it's got four arses!

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Offline turnipsock

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How Does Astro The Astronaut Check His Weight ?
« Reply #32 on: 16/05/2008 16:44:01 »

Alternatively, he could be accelerated and then deccelerated.


What! Like in an inertia balance you mean?
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Offline LeeE

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How Does Astro The Astronaut Check His Weight ?
« Reply #33 on: 17/05/2008 21:53:14 »
Oh, is that what they're called? [;D]
...And its claws are as big as cups, and for some reason it's got a tremendous fear of stamps! And Mrs Doyle was telling me it's got magnets on its tail, so if you're made out of metal it can attach itself to you! And instead of a mouth it's got four arses!