# Pressure Force on a partially submerged surface

• Engineering
• patricio ramos
In summary, the conversation discusses the calculation of pressure in a submerged plate. The question is whether the pressure should be multiplied by the area that is submerged (25m^2) or the entire area of the plate (30m^2). The person suggests that there may be a mistake in the thinking process and encourages the individual to work on their solution and seek guidance if necessary.
patricio ramos
Homework Statement
A 6-m-high, 5-m-wide rectangular plate blocks the end
of a 5-m-deep freshwater channel, as shown in Fig. P3–75.
The plate is hinged about a horizontal axis along its upper edge
through a point A and is restrained from opening by a fixed ridge
at point B. Determine the force exerted on the plate by the ridge.
Relevant Equations
P = pgh
F = PA
Once I get the pressure, do I have to multiply times de area that is submerged (in this case it would be 25m^2), or do I take the whole area of the plate, including the part that is not submerged (in this case it would be 30 m^2)

Thanks

#### Attachments

• afigura.png
1.4 KB · Views: 240
Hi,

Would it make a difference if the plate were 12 m high instead of 6 ?

There is something else going wrong in your line of thinking, it seems: what do you mean with 'the pressure' ?

Why don't you get started on your solution and post what you have worked out. PF will steer you if things go wrong

## 1. What is pressure force on a partially submerged surface?

The pressure force on a partially submerged surface is the force exerted by a fluid on an object that is partially submerged in it. This force is caused by the pressure of the fluid acting on the surface of the object.

## 2. How is pressure force calculated on a partially submerged surface?

The pressure force on a partially submerged surface can be calculated by multiplying the pressure of the fluid by the surface area of the object that is submerged. The formula for this is F = P x A, where F is the pressure force, P is the pressure of the fluid, and A is the surface area of the submerged object.

## 3. What factors affect the pressure force on a partially submerged surface?

The pressure force on a partially submerged surface is affected by the density of the fluid, the depth of the object's submersion, and the shape and size of the object. The pressure force also increases with the depth of the fluid, as the weight of the fluid above the object increases.

## 4. How does the angle of the submerged surface affect the pressure force?

The angle of the submerged surface can affect the pressure force by changing the surface area of the object that is submerged. A larger surface area will result in a greater pressure force, while a smaller surface area will result in a smaller pressure force. The angle can also affect the direction of the pressure force, with a perpendicular surface experiencing a vertical pressure force and an angled surface experiencing a diagonal pressure force.

## 5. Can the pressure force on a partially submerged surface be negative?

Yes, the pressure force on a partially submerged surface can be negative if the object is buoyant and the fluid is pushing it upwards. This is known as an upward or buoyant force and is caused by the difference in pressure between the top and bottom of the object. In this case, the pressure force is acting in the opposite direction of the gravitational force, resulting in a negative value.

Replies
9
Views
2K
Replies
9
Views
2K
Replies
6
Views
15K
Replies
2
Views
1K
Replies
13
Views
2K
Replies
3
Views
1K
Replies
3
Views
2K
Replies
6
Views
684
Replies
6
Views
1K
Replies
16
Views
2K