The water pressure and buoyancy

2018年4月12日

The water pressure

It is pressure to occur because of weight of the water pressure … water

Characteristic of the water pressure

The water pressure acts from every direction
The water pressure acts on the surface of the object perpendicularly
The water pressure is proportional to the depth from the surface of the water (if depth is the same, the water pressure agrees)

The water pressure takes 100Pa per 1cm in depth.

Buoyancy

Ascending power to act on an object in the buoyancy … water

※I made an article of the buoyancy to demand in five seconds. When I do not understand it even if I read this article, please come to reference

[exercise]

As shown, the power to act on the object which was able to sink into the water is any N, or answer it.

Buoyancy

The water pressure to depend on the top surface is 10000Pa in being 1m in depth

The water pressure to depend on the undersurface is 20000Pa in being 2m in depth

The power to depend on the top surface is 10000Pa *0.0001 ${m}^{2}$ ＝1N

The power to depend on the undersurface is 20000Pa *0.0001 ${m}^{2}$ ＝2N

Power of 1N acts from power of 2N, the top from the bottom.

Power of 1N will act upward by composing the power.

In addition, the relations of ups and downs are as follows.

Gravity＞In the case of buoyancy, I am depressed

In the case of gravity <buoyancy, I am isolated

Or,

Density of the object＞In the case of liquid density, I am depressed

In the case of the density of the density <liquid of the object, I am isolated

When I do not understand a used expression, the pivot checks a unit of the pressure

※Let’s be careful not to confuse power with pressure.

Archimedes’ principle

The buoyancy to act on an Archimedes’ principle … object becomes equal to the liquid weight that an object pushed aside.

I demanded buoyancy with differences between power and power from the undersurface from the top surface some time ago, but can demand buoyancy easily when I use Archimedes’ principle.

It is a method calling for the buoyancy using Archimedes’ principle

①I find the volume of the sinking object.

1 ${cm}^{2}$ *100cm = 100 ${cm}^{3}$

②I find the liquid mass for the volume.

The density of the water is 1g/ ${cm}^{3}$ So it is 100 ${cm}^{3}$ The の water becomes 100 g.

③I demand gravity of the water.

The gravity of 100 g of water is 1N.

Thus, the buoyancy is identified as 1N.

※①The で volume ${cm}^{3}$ When I appear, I OK it even if I demand buoyancy by dividing the number by 100

I return to a list of units

Physics

Posted by Lese