The human body special mass

So you agree that lying on my belly on concrete block by my weight 59 kg must damage my belly severely just like putting the 59 kg rock on my belly.
In my experiment I did so. No contact on the chest or so, just the belly. And I bear it for 1 minute. Not even slight injury.



Also my body is balanced.

 

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OK, I think you are taking quite a lot on your lower ribs, though. I didn't say putting a 59kg weight just on your belly would damage it severely. I said might injure yourself, that's all. If you were to place the object you are draped across on your belly and put a weight on it, you would be able to manage it without too much trouble, so long as you braced your abdominal muscles appropriately. At the rowing club we sometimes would get someone to stand on our abdomens for fun, just to show how strong those muscles were.

 

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I took it to be

• lying on his belly on the block his belly is not crushed
• but
• the block on his belly would (yes it would) crush his belly

Yes that is so so silly but it is how I read what he posted

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It is. For the same area " The belly area" a smaller force" The bock" gives greater pressure" crushes the belly" while a greater force 59 kg do not crush the belly" lower pressure"

In the experiment What is the force f in the scale when the human lifts his body? what its value and why?

 

All this is true for objects, not for a human body. I do not argue about that.
You did not answer my question. In the experiment. The scale shows 60 kg for the human body weight, when the human lifts his body the scale reading increases by 60+f kg, f is the increment in the weight, what this f kg represents?

 

Calves' mucsles and feet muscles are weak so they lift the massive human 60 kg many times with force f of only several kilograms.

 

How it’s possible for an ordinary person to lift a car

https://www.bbc.com/future/article/20160501-how-its-possible-for-an-ordinary-person-to-lift-a-car

Makes interesting reading and perhaps something to chew the cud over

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Yahya A.Sharif,

Your posts about "The human body special mass" are very, well, fascinating...


You can perform a simple two-part experiment to prove your theory that:

You will need a volunteer from the audience registering 60 kg (or more) on a scale.



Part one relates to belly muscles:

Have your volunteer stand on your stomach for a minute. Extra points if your volunteer shows 80+ kg on the scale or if s/he jumps up and down a few times. Record the experiment on video.



Part two illustrates how a human

but

Just record a video of you lifting your volunteer up many times with your arm muscles.



When you post the videos here everyone will understand.

Very simple...

 

In the video I measure my maximum calves and feet muscles force which turns out to be approximately 8 kg-force which is relatively weaker compared to other human body muscles.
I must exert the maximum 8 kg-force or less to lift my body as in the video. This force of 8 kg-force I lift my body with is far less than my weight 59 kg-force.
The movement of pushing the scale is equivalent to the movement to lift my body.




This 8 kg-fore or less is equivalent to the force "f " I lift my body with in the experiment:

This is not an ordinary person.

 

The human lifts his body with constant speed " a=0" the force "f" is a constant . This constant f is the force a human lifts his body with.

 

Thank you. I will think about it.

 

All I can tell you is that you have done a poor job on the experiment because the average person can easily produce a force of 59 kgf with one foot using their calf muscles.

 

This means if I am lying on the ground and put a 59 kg rock on one foot and exert force with my calf muscles of one leg then I can lift the rock that short distance with one foot ? An average human cannot do that. But an average human can lift his body like someone tries to pick a fruit from a tree short distance several times

 

That's because the leverage is different in each of those cases. Ergo, apples and oranges.

 

When I lie down on the ground and my legs are up and then putting a rock of 59 kg on foot sole and then tries to lift it not by my legs but by my foot " one foot" short distance equivalent to moving my body up short distance like someone tries to pick a fruit from a tree with one foot. The two movements are equivalent, are not they? I cannot lift the rock 59 kg but I can lift my body 59 kg several times.

Let's say for the experiment the foot is 20 cm or 0.2 meters long , Now let's calculate for a 0.2 m lever. First the lever will be class 2 :
The weight for 59 kg will be 59 kgf. Class 2 is the fulcrum at the toes , and in this case both the weight of my body and the force of my calves muscles I lift my body with will be at the ankle(The body can be balanced to be exactly vertical) The feet muscles specifically will be distributed throughout the feet but let’s assume we get their maximum strength in which the feet muscles are concentrated on the ankle:

F: the force of my weight

f: the force of my muscles.

L: the distance of the weight from the ankle to the toes.

l: distance of the muscles force from the ankle to the toes.

f * l=FL.

F=59 kgf and L=l =0.2 meters

f*0.2=59*0.2

f=59 kgf

The force needed to lift my body is 59 kgf. The foot as a lever does not change the force needed to lift the human when the human lifts his body like someone tries to pick a fruit from a tree. I must exert a force equals to my weight 59 kgf to lift my body(or the smallest force that is greater than my weight 59 kgf) In other words the foot as a lever does not increase or decrease the force to lift my body, the force to lift my body must be greater than my weight 59 kgf.

 

Of course they can.

 

Yes, you can raise a 59 kg weight if you can raise your body.
In the gym where I work out there is an apparatus that allows you to lift weights in an inclined position. I can easily lift a 60 kg weight with 1 foot using my calf muscles.

This thread is terribly silly. The issue is that you cannot or will not perform a simple experiment to prove it to yourself.