Solid pressure is primarily the first enemy of builders. Due to the fact that there is pressure of solids, it is impossible to implement some projects in principle. It is interesting that the ancients, on the contrary, used this property, creating magnificent structures. Pyramids and many other architectural monuments - all these are the results of painstaking work in creating magnificent masterpieces. Consider what pressure is relative to solids.
The pressure formula of solids, found back in those days, reads:
P = F / S,
those. the force acting on the surface is the pressure of the object.
It is worth noting that, in fact, the pressure force of the body is always positive and acts in both directions. Here Newtonās First Law applies - the force of action is equal to the strength of the counteraction. Applicable to life - the pressure that the weight of the building exerts will be the same for its lower layers and foundation. Therefore, construction designers always calculate whether the foundation can withstand such a building. Of course, other factors also enter into this calculation (wind force from the roof, groundwater, seismic activity, etc.).
Why does a person need to disperse their weight over a larger surface? And then remember the needle or knife. Both have a sharp part for better penetration. Now remember the skis and tracked tractors. Skiers do not fall into the snow, and tractors have good cross in swamps, as they have a large contact area - for less immersion. This is reflected in the basic formula showing the pressure of solids - with the same force, but with a different area, the pressure will be different. It will be inversely proportional to the area. Those. the larger the area, the greater the pressure. And vice versa.
Now back to the builders. Why is their pressure a big headache? It's all in that same square. After all, the stronger the material, the harder it is. Remember the heavy concrete slabs. Of course, in our time there are many durable and lightweight materials. But here, not everything is simple. Any construction project is valued for profitability. And if the price of such super-materials is high, then the construction estimate will be large. As a result, either the customer will not pull on finances, or the project will pay off for a very long time. But we already said above that the ancients used the pressure of solids in their favor.
In those days, building materials were quite limited in assortment and quantity. After all, there was no mining industry, but the stone was carved manually. There were no binding elements such as concrete or mortar. It was necessary to use the pressure of solids instead of fastening. The fact is that the greater the pressure, the more strength is required from the materials. But on the other hand, it is also a great friction force. And she, as you know, can be of great importance. As a result, we get that the fasteners were not needed, everything rested on gravity and friction.
Now imagine what pressure the train has on the rails - 300,000 kPa !!! At a pressure of a specialized caterpillar tractor - 20 kPa. A rather interesting point, it would seem, a heavy swamp tractor, creates a relatively low pressure on the ground. This allows him to move through impassable and swampy areas due to the wide tracks. If we talk about the friction mentioned above, then it can be of different types and is determined by the formula:
F = Āµ Ć N, [N]
where F is the friction force [N],
Āµ is the coefficient of friction,
N is a normal reaction [N].
The pressure force is seen to have both a positive and a negative moment. Nature has adapted to this phenomenon. People from ingenious simple designs went on to invent new materials and technologies. There is such a phenomenon in nature and must be reckoned with.