Решение на момент правки #17946 от , автор Arman. Это не текущая версия.

Statement

4.5.12. a. The sum of the forces acting on the volume of liquid highlighted in the figure is zero. Using this fact, determine the height to which the liquid rises along a vertical wall. The contact angle is . The surface tension and density of the liquid are and , respectively.

b. To what height will water rise along a vertical wall that it wets completely?

For problem $4.5.12$

Solution

The sum of the forces acting on the volume of liquid highlighted in the figure is zero,so let's write force balance to the axis:

where is an average pressure of the liquid.As pressure linearly increasing with depth we get:

Plugging eq(2) into eq(1) we get rise height of the liquid:

In the case of complete wetting, the contact angle is zero,so:

For the water , and ,so:

Answer

a. b.3.9mm