# Do you feel an acceleration in space

## The human body, scientists and acceleration

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### Author: Quantium40 01.09.17 - 15:26

> The human body can achieve the acceleration that is necessary to achieve a
> To reach a speed of 4,000 kilometers per hour, only for a short time
> endure.

4000km / h are 1111.11m / s.
With an acceleration of 1g, this can be reached in 113.3s or just under 63km.
Amazingly, the average person can endure this acceleration all their life.

### Author: Sarcastic 01.09.17 - 17:58

Quantium40 wrote:
--------------------------------------------------------------------------------
>> the human body can achieve the acceleration that is necessary to achieve a
>
>> To reach a speed of 4,000 kilometers per hour, just for
> short time
>> endure.
>
> 4000km / h are 1111.11m / s.
> With an acceleration of 1g, this is reached in 113.3s or after
> almost 63km.
> Amazingly, the average person keeps this acceleration
> his whole life off.

But with such an argument you won't get very far at AFD. You can't compare that. We were here before the trains. It works very differently. But still, 1G acceleration increases a bit with 1G attraction on the body.

### Author: Rather 01.09.17 - 18:26

> exponentiated
Mh ... no.
If the seats etc. are not inclined, then you have 1g backwards and 1g downwards, a right-angled triangle -> according to Pythagoras together root (1² + 1²) = root (2) = 1.41g

### Author: Thunderbird1400 01.09.17 - 18:39

Quantium40 wrote:
--------------------------------------------------------------------------------
>> the human body can achieve the acceleration that is necessary to achieve a
>
>> To reach a speed of 4,000 kilometers per hour, just for
> short time
>> endure.
>
> 4000km / h are 1111.11m / s.
> With an acceleration of 1g, this is reached in 113.3s or after
> almost 63km.
> Amazingly, the average person keeps this acceleration
> his whole life off.

According to the definition, G-forces are loads that can be felt by changing the direction or size of the speed.

When you stand on the ground, your speed doesn't change, so you don't feel any G-forces either (only the static weight of your body caused by the gravitational pull). But if you jump out of the airplane, you will feel the G-forces very clearly (at least as long as your speed increases), and you will "only" be accelerated with g = 9.81m / s².

Now imagine, you have this feeling (like when you jump out of the plane in the beginning) for 113 seconds on the train. What do you mean, what percentage of the passengers then vomit or the cycle collapses.

Edited 3 times, last on 09/01/17 6:44 PM by Thunderbird1400.

### Author: Sarcastic 02.09.17 - 03:11

Thunderbird1400 wrote:
--------------------------------------------------------------------------------
> Quantium40 wrote:
> ---------------------------------------------------------------------------
> -----
>>> the human body can accelerate it, which is necessary to
> a
> >
>>> To reach a speed of 4,000 kilometers per hour, just for
>> a short time
>>> endure.
> >
>> 4000km / h are 1111.11m / s.
>> With an acceleration of 1g, this is reached in 113.3s or after
>> almost 63km.
>> Amazingly, the average person holds this
> Acceleration
>> his whole life off.
>
> As already written in the other thread (why is the same topic still
>
> According to the definition, G-forces are loads that are caused by directional or
> Senses change in speed.
which, as you explain wrongly, can add or subtract to gravity.

> When you stand on the ground, your speed does not change,
> So you don't feel any G-forces either (only the static weight force
> your body caused by gravity).
Your body doesn't fall. So you are constantly working against gravity. So you feel 1 G. If you sit in a centrifuge and weigh 80 kilos, you have a G. If this accelerates until you weigh 160 kilos, you have exactly 2 G. If you would have 0 G if you were on the ground, you could you are floating and you would have a weight of 0 pounds.

But do you jump out of the
> Airplane, you can feel the G-forces very clearly (at least as long as you
> your speed increases), and you will "only" with g = 9.81m / s²
> accelerates.
Wrong you feel 0 G when jumping out of an airplane. Because you have no opposing force. Only the air resistance would act with increasing speed. When you have reached the maximum falling speed you will feel exactly 1 G.

> Now imagine this feeling (like in the beginning when you left the
> Plane jumps), you have 113 seconds on the train. What do you mean, how much
> Percentage of passengers then vomit or the cycle collapses.

As long as you don't get sick from the speeding past, not much happens with constant acceleration except that you have a short workout.

### Author: honna1612 02.09.17 - 03:13

When you get off the plane you can feel weightlessness. Acceleration is only noticeable if you do NOT accelerate towards earth with 1g. So always except in the first moments of freefall.

### Author: Thunderbird1400 02.09.17 - 10:47

I can see that there is a problem of definition here.

According to this definition of G-force (yes, it is from Wikipedia, please give me a better definition):
"g-forces are called loads that act on the human body, an object of daily use or a vehicle due to strong changes in size and / or direction of speed."

... that would mean that you feel a "G-force" of zero while standing on the ground, because the speed in relation to the reference system does not change. So is the above definition wrong?
It is quite clear to me that you can feel the weight that results from the gravity (F = m * a), i.e. around 800N for me, which I feel in my feet, joints, bones, etc. I only call this weight force and not "G-force" according to the definition above.

When I jump out of the plane, at first I no longer feel the weight, it is zero, and then it increases again continuously. But as I said, I call this weight force. The "G-force" according to the above definition would not be zero at the beginning as long as there is a change in speed.

So we all mean the same thing, but the definition of the term is not clear to me.

Edited 2 times, last on 02.09.17 10:54 by Thunderbird1400.

### Author: Rather 02.09.17 - 11:04

Take a look at the English wiki, I find the definition much more understandable.
> The g-force (with g from gravitational) is a measurement of the type of acceleration that causes a perception of weight.

The following lines also clarify a few things. For example, that there is no g-force in free fall.

### Author: Thunderbird1400 02.09.17 - 11:09

Hmm yes ok, the English definition makes more sense.

### Author: Sarcastic 02.09.17 - 14:48

Thunderbird1400 wrote:
--------------------------------------------------------------------------------
> I can see that there is a problem of definition here.
No, you only have a little imagination problem that as a person on earth you always feel about 1 G. Through evolution, the body is adapted in such a way that it also needs this force to survive. A year-long stay in space at 0 G still brings a lot of health problems with it.

> According to this definition of G-force (yes, it is from Wikipedia, you may like me
> give a better definition):
> "g-forces are called loads that are due to strong changes in
> Size and / or direction of the speed on the human body,
> act on an object of daily use or a vehicle. "
That's not wrong either. However, as already discussed, there is the basic effect of gravity when one is exposed to a force of attraction. You are constantly changing your speed because you are always counteracting a G on earth. If you jump off a shed, you have almost 0 G (air resistance) for a short time. If you then land on the ground, you counteract the force completely again.

> ... that would mean that you have a "G-force" of zero while standing on the ground
> feels, because the speed to the reference system does not change. So
> is the above definition wrong?
But you counteract the actual acceleration due to gravity, which corresponds to 1 G completely.

> It is completely clear to me that you can feel the weight that is moving
> results from the gravitational pull (F = m * a), so for me about 800N, which I use in
> feel my feet, joints, bones etc. I just call it weight
> and not "G-Force" as defined above.
Colloquially, of course, you say that you can feel your weight. But the noticeable weight is only noticeable because gravity acts on you and on earth this is 1 G. You feel lighter on the moon or Mars because the gravity is lower there. On Mars, the gravitational acceleration is 3.69 m / s squared. Accordingly, only 0.377 G would act on you permanently. When you go up on Mars with a rocket that accelerates with a G, you feel
1,377G. With the same acceleration you will feel 2 G on earth

> When I jump out of the plane, at first I don't feel the weight
> more, it is zero, and then increases again continuously. That denotes
> But as I said, I as weight force. The "G-Force" after the above
> Definition would then initially not be null as long as there is a
> There is a change in speed.
Take a helicopter as an example. Because at the beginning of the airplane you also have the braking effect through the air, which results from the speed of the airplane and you feel this too. The gravity acts on you here constantly. You are weightless as soon as you jump. Your weight would increase noticeably up to the maximum falling speed. Then you feel 1 G again

> So we all mean the same thing, but the definition of the term
> is not clear to me.
Simply separate the existing 1 G from the G acceleration forces, then that fits.

### Author: Sarcastic 02.09.17 - 14:59

honna1612 wrote:
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> When you get off the plane you can feel weightlessness. acceleration
> is only noticeable if you are NOT accelerating towards earth with 1g.
You can also feel this. Only you have become so used to it that you do not realize it permanently. People who wear glasses have also got used to the weight of their glasses and usually do not take them actively. Nevertheless, the weight of the glasses remains.

### Author: Rather 02.09.17 - 15:13

> You can feel this too.
When you are in free fall you cannot feel any acceleration (or measure it in the system).
> Nevertheless, the weight of the glasses remains.
The mass remains, the weight is gone. So in free fall.

### Author: Sarcastic 02.09.17 - 15:17

Eheran wrote:
--------------------------------------------------------------------------------
>> You can feel this too.
> When you are in free fall you cannot feel any acceleration (or in
> Measure system).
>> Nevertheless, the weight of the glasses remains.
> The mass remains, the weight is gone. So in free fall.

You don't really feel the acceleration due to gravity without counterforce. I understood it to mean that you assume your own acceleration. Because you always feel an acceleration.

### Author: Rather 02.09.17 - 15:27

> I understood it to mean that you are assuming your own acceleration.
It was about "jumping out of the plane", that is, free fall.

> Because you always feel an acceleration.
Just not. If you simply fall against gravity you cannot feel it. So, for example, in free fall as in orbit around the earth, which corresponds to a non-stop "falling to earth", only that one is so fast that one "falls around the earth" and not onto it.

### Author: Thunderbird1400 02.09.17 - 16:35

Sarkastius wrote:
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> No, you only have a little problem of imagining that you are a human being
> the earth always felt about 1 G.
No, I don't have an idea problem there. I wrote that it is absolutely clear that you can feel the weight caused by gravity on the ground.

Sarkastius wrote:
--------------------------------------------------------------------------------
> That's not wrong either. However, as previously discussed, there are those
> Basic effect of gravity when exposed to a force of attraction
> is. You are constantly changing your speed because you are always on earth
> counteract a G.
I'm constantly changing my speed when I'm on the ground because of gravity? You have to explain that in more detail. I'm changing the speed in relation to what? When I stand still on the ground, I don't change my speed. So how should the above Definition be correct?

Edited 4 times, last on 02.09.17 16:38 by Thunderbird1400.

### Author: Sarcastic 02.09.17 - 17:16

Eheran wrote:
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>> I understood it to mean that you were accelerating yourself
> going out.
> It was about "jumping out of the plane", that is, free fall.
>
>> Because you always feel an acceleration.
> Not exactly. If you simply fall against gravity, it is not closed
> feel. So in free fall as in orbit around the earth, what a
> The equivalent of "falling to earth" without a break, only that you can do it as quickly
> is that one "falls around the earth" and not on it.
Yes, that's exactly how I wrote it before. You will not notice the acceleration due to gravity that you are exposed to without a counterforce. But an acceleration is an acceleration and you notice it. These are two different things. When you are accelerating in a car, you have the acceleration and the gravity.

### Author: Rather 02.09.17 - 21:42

> You do not notice the acceleration due to gravity that you are exposed to without a counterforce.
> But an acceleration is an acceleration and you notice it.

### Author: Sarcastic 03.09.17 - 01:58

Eheran wrote:
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>> You will not notice the acceleration of gravity that you are exposed to without
> Counterforce.
>> But an acceleration is an acceleration and you notice it.
>
> Don't you see the contradiction?

No you?

### Author: chithanh 03.09.17 - 10:23

Eheran wrote:
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> If you simply fall against gravity, it is not closed
> feel. For example in free fall as in orbit around the earth

That is not completely right. Tidal forces act even in free fall / orbit. This is why, for example, the moon has always turned the same side of the earth.

### Author: Rather 03.09.17 - 11:45

I want to see that someone can feel something like this. It is no different when standing, the head is further away (less gravity) than the legs. However, this is simply irrelevant for an object with ~ 2m.

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