My belly is on the block not touching any bones and the rest of my body is on air.

The image on the video looks like parts of your legs and arms are in contact with the sides of the block. That might mean that there are some friction forces applied, meaning that your entire weight is not supported by your stomach. However, that is likely to be a small fraction of your weight.[/QUOTE]

The only answer is my theory. I am not magical every one can lie on a concrete block. And everyone knows that putting a 15 kg block " **forth the weight 60 kg**" let alone a 60 kg rock will damage their belly.

You have several misconceptions, as has previously been pointed out.

Suppose you were to lie on a concrete block that weighs the same as a small car: say 2000 kilograms. The force exerted on your stomach will not then be 2000 kg. Lying on your back with that block (car) on your stomach is not the same situation as lying on your front on top of the block (car).

If you hold an object that has a mass of X kilograms, so that object does not touch the ground, then the downward force on your body due to the object will be equivalent to X kilograms. Hold a 50 kg rock and the downward force on your body due to the rock will be 50 kg. It doesn't matter what your body mass is. It also doesn't matter whether that 50 kg is held in your hands or on your stomach or balanced on your head. The rock will always exert a total downwards force on your body equivalent to 50 kg.

So, why does it feel different holding a 50 kg rock with your hands than it feels when you lie down and place the 50 kg rock on your stomach? Why does it feel different if you balance the 50 kg rock on your head? The reason is that how it feels doesn't just depend on the total force exerted on your body, which, as we have already established, is equivalent to 50 kg in all cases. How it feels also depends on the

*pressure*, which is the force exerted

*per unit area*. The pressure on your body is determined by the total contact area between your body and the rock. In general, a large contact area will have low pressure, while a small contact area will have high pressure. If your 50 kg rock is a large flat slab and you lie on the floor with the rock on your stomach, that 50 kg force will be spread over the whole area of your stomach, resulting in a relatively low pressure. That might mean that it doesn't hurt much, because the compressive force on your stomach

*per unit area* is tolerable. On the other hand, if that 50 kg of rock consists of a long tube of rock and you try to balance that tube with one of its end surfaces (say 2 cm diameter) on the centre of your stomach, then you might rapidly find that your stomach is impaled by a tube of rock, because the resulting pressure (force

*per unit area*) will be much higher. In both cases, though, note that the force is still equivalent to 50 kg.

Consider the following two cases, then:

1. A 50 kg flat slab of rock lies on the ground. You lie across the slab such that only the area of your stomach (say 100 square centimeters) is in contact with slab.

2. You lie on the ground, face up. The same 50 kg slab of rock is placed on your stomach, so that the contact area is the same as in case 1 (100 square centimetres).

In case #2, the force on your stomach will be equivalent to the 50 kg weight of the rock. The pressure will be that force divided by 100 square centimeters.

In case #1, the force on your stomach will be equivalent to

*your body weight*, since in that case your stomach obviously is not supporting the rock; it is supporting your body weight.

If your body mass is 70 kg, then case 2 is going to hurt

*less* than case 1.

If your body mass if 40 kg, then case 2 is going to hurt

*more* than case 1.

Take this to an extreme. Replace the 50 kg rock by a 2000 kg car.

Case 1: you lie on top of the car, bending your body so that only your stomach is in contact. The force your stomach is supporting is your body weight, say 70 kg. You will be able to tolerate this for a time, given the pressure.

Case 2: you lie on the ground and have the 2000 kg car placed on your stomach. In this case, your stomach will need to support 2000 kg of force. Your stomach is not going to come out of this situation very well.

Any questions?