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A truly equivalent scenario would involve placing an object of the same weight on your abdomen. Hypothetically, placing a 63.4 kg block with an area of 0.2x0.2 meters on my abdomen would be fatal. However, my own body weight was 63.4 kg, I could lie on a 0.2x0.2 meter concrete block for one minute without experiencing any pain or injury.
Science does not recognize the concept of "squeezed" pressure; pressure must remain the same when the force, material, and area are unchanged.
Quote from: Yahya A.Sharif on 03/08/2025 14:48:50Science does not recognize the concept of "squeezed" pressure; pressure must remain the same when the force, material, and area are unchanged.Not so. The pressure on your stomach might be the same, but the pressure acting on your back would be different in the two scenarios. In one, the ground is pressing against your back and in the other it is not.
My experiment does not compare the pressure on my back; it compares the pressure on my abdomen.
However, placing four 15‑kg concrete blocks directly on my abdomen would be fatal.
What was the surface area of the concrete block you laid on top of?
Quote from: Yahya A.Sharif on 04/08/2025 10:53:54However, placing four 15‑kg concrete blocks directly on my abdomen would be fatal.You seem to be just restating your opinion and then claiming reality does not agree with it.
Quote from: Bored chemist on 04/08/2025 22:26:07Quote from: Yahya A.Sharif on 04/08/2025 10:53:54However, placing four 15‑kg concrete blocks directly on my abdomen would be fatal.You seem to be just restating your opinion and then claiming reality does not agree with it.So, you're saying that placing four 15‑kg concrete blocks on an average human abdomen is considered safe?
Quote from: Yahya A.Sharif on 05/08/2025 15:30:24Quote from: Bored chemist on 04/08/2025 22:26:07Quote from: Yahya A.Sharif on 04/08/2025 10:53:54However, placing four 15‑kg concrete blocks directly on my abdomen would be fatal.You seem to be just restating your opinion and then claiming reality does not agree with it.So, you're saying that placing four 15‑kg concrete blocks on an average human abdomen is considered safe?It isn't me that's saying it.The laws of physics are saying it.If you can support your 65 KG weight on a 20 cm by 20 cm concrete block then it is almost certain that you can support 65 Kg of concrete on your abdomen.(The uncertainty results from the fact that the human body isn't completely symmetrical)Nobody is saying it would be comfortable, or a good idea.Have you done what was asked and supported your whole weight on just 20 by 20 as someone suggested- perhaps on top of a farm gate post?If you say that's safe, then the laws of physics say that the reverse- you supporting the blocks- is also safe.
To try to support one's entire body weight on a 0.2x 0.2 block would be very difficult unless done at height as BC has suggested. It would be next to impossible to prevent some load bearing via the legs and upper body.
QuoteHypothetically, placing a 63.4 kg block with an area of 0.2x0.2 meters on my abdomen would be fatal. However, my own body weight was 63.4 kg, I could lie on a 0.2x0.2 meter concrete block for one minute without experiencing any pain or injury. Why the hypothesis? Try it! Just find a farm gatepost (they are usually about 15 x 15 cm) and nail a 20 x 20 piece of 15 mm plywood to the top. Unless you are a trained gymnast or bodybuilder, I doubt that you would manage more then 10 seconds suspended prone by your abdomen.Less dangerously, stack four house bricks to make a pile 215 x 215 mm x 130 mm high. Drape yourself over them, then raise your arms and legs so that your entire weight is borne by the bricks. If your paraspinal muscles aren't strong enough, just use one layer of bricks (65 mm high), get a "friend" to truss you to a pole (feet, hips, shoulders) and when you are steady, put your hands behind your head.
Hypothetically, placing a 63.4 kg block with an area of 0.2x0.2 meters on my abdomen would be fatal. However, my own body weight was 63.4 kg, I could lie on a 0.2x0.2 meter concrete block for one minute without experiencing any pain or injury.
For the sake of being thorough, I just got done performing a similar experiment. I just got my brother, who weighs 158.2 pounds (71.9 kilograms) at the moment, to stand on my stomach. It wasn't comfortable and I had to tense my abs, but it wasn't painful either. Let alone lethal. That's more weight than 60 kilograms of concrete. The issue is the surface area, since measuring the surface area of feet isn't straightforward. Still, I wouldn't expect it to be all that far off from 20 centimeters by 20 centimeters.