Force of pressure

Pressure is the relation of force that actsperpendicular to the surface, to the area of ​​this surface. The pressure in pascals is measured (1 Pa is the pressure that a force of 1 newton produces when applied to a surface of one square meter).

The power of pressure is such a force thatpressure on a certain surface. It is measured in Newtons (1 N). The smaller the surface area to which this pressure is applied, the less can be the applied force, with which you can achieve the expected effect.

The pressure force acts on the surfaceperpendicular to it. It can not be identified with pressure. To determine the pressure, it is necessary to divide its force into the area of ​​the surface on which it appears. If you apply the same force to affect the surface of a different area, the pressure will be greater where there is less footprint. If you know the pressure and surface area, then you can learn the force of pressure by multiplying the pressure by the area.

The force of normal pressure is always necessarily perpendicular to the surface on which it is affected. According to Newton's third law, it equals the strength of the support reaction according to its modulus.

The role of force of pressure is able to play any power. This may be the weight that deforms the support, or the force that presses any body to a certain surface, and so on.

In contact with solid bodies of a liquidThey act on them with a certain force, which they call it - the force of pressure. In everyday life, you can feel the effect of such a force by covering your finger with a tap hole, from which water flows. If you put mercury in a rubber canister, you can see that its walls will begin to bulge outward. The force of fluid pressure can also affect other liquids.

When the solids come into contact, the elastic forceoccurs when the shape or volume changes. In liquids, such forces do not arise when the shape changes. The lack of elasticity with respect to changes in shape causes the mobility of liquids. When the liquids are compressed (changing their volumes), the elastic forces will manifest themselves. They are called the force of pressure. That is, if the liquid acts on pressure-sensitive other bodies in contact with it, then it is in a compressed state. The more compressed the fluid, the stronger the pressure resulting from this force will be.

As a result of compression, the density of substancesincreases, so the fluids have elasticity, manifested in relation to their density. If the vessel is closed with a piston and the load is placed on top, then when the piston is lowered, the liquid begins to contract. It will create a force of pressure, which will balance the weight of the piston with the load on it. If we continue to increase the load on the piston, the liquid will continue to compress, and the increasing pressure force will be directed to balancing the load.

All liquids (to a greater or lesser extent) are able to contract, so it is possible to measure the degree of their compression, which corresponds to a certain pressure.

To reduce pressure on the surface, in the case ofIf it is not possible to reduce the force, it is necessary to increase the area of ​​the support. Conversely, in order to increase the pressure, it is necessary to reduce the area to which its force acts.

The gas molecules are not bound (either too weaklyare connected) with each other by the force of interaction. Therefore, they move chaotically, almost freely, filling the entire volume of the vessel provided to them. In this regard, the properties of the gas differ from the properties of liquids. For gases, the density depends on the pressure to a much greater extent than for liquids. The common thing between them is that the pressure of both fluid and gas does not depend on the shape of the vessel into which they can be placed.