Absolute pressure at an ocean depth

In summary, at an ocean depth of 550 m, the pressure is 5609880 Pa, assuming a sea water density of 1022 kg/m3 and an air pressure of 101.3 kPa. For part (b), the force needed to counterbalance the water pressure on a circular submarine porthole with a diameter of 32.0 cm can be calculated by dividing the pressure by the area of the porthole.
  • #1
jenha14
11
0
a) Calculate the pressure at an ocean depth of 550 m. Assume that the density of sea water is 1022 kg/m3 and that the air above exerts a pressure of 101.3 kPa.
b) At this depth, what force must the frame around a circular submarine porthole having a diameter of 32.0 cm exert to counterbalance the force exerted by the water?

I found the answer for (a) to be 5609880 Pa, but I am stuck on part (b).
 
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  • #2
Assuming the inside of the sub is at atmospheric pressure all you need is the water pressure at that depth.
Since pressure is force / area. You have the pressure,you can get the area of the porthole so hat is the force?
 
  • #3


For part (b), we can use the equation for pressure (P = F/A) to find the force exerted by the water on the porthole. The area (A) of the porthole can be calculated using the formula for the area of a circle (A = πr^2), where r is the radius of the porthole (16 cm). This gives us an area of 201.06 cm^2 or 0.020106 m^2.

Plugging in the values for pressure (5609880 Pa) and area (0.020106 m^2) into the equation, we get:

5609880 Pa = F/0.020106 m^2

Solving for F gives us a force of 112.61 kN. This is the amount of force that the frame around the porthole must exert to counterbalance the force of the water at a depth of 550 m.

As a scientist, it is important to note that this calculation is based on the assumptions made in part (a), such as the density of sea water and the pressure of the air above. These values may vary in different ocean environments and can affect the accuracy of the calculation. Additionally, the force calculated is only for the water pressure and does not take into account any other external forces that may be acting on the porthole. It is important to consider all factors and potential sources of error when making calculations and conducting experiments.
 

1. What is absolute pressure?

Absolute pressure is the total pressure exerted by a fluid, including both the atmospheric pressure and the pressure from the weight of the fluid itself. It is measured in units of force per unit area, such as pounds per square inch (psi) or pascals (Pa).

2. How does depth affect absolute pressure in the ocean?

The deeper you go in the ocean, the greater the absolute pressure becomes. This is because the weight of the water above you increases as you descend, adding to the atmospheric pressure. For every 10 meters of depth, the pressure increases by about 1 atmosphere (14.7 psi).

3. How is absolute pressure calculated at a certain depth in the ocean?

To calculate absolute pressure at a specific depth in the ocean, you would need to know the density of the water at that depth, the acceleration due to gravity, and the atmospheric pressure. The formula for absolute pressure is P = ρgh + Patm, where P is absolute pressure, ρ is density, g is acceleration due to gravity, h is depth, and Patm is atmospheric pressure.

4. What is the difference between absolute pressure and gauge pressure?

Absolute pressure includes the atmospheric pressure, while gauge pressure only measures the pressure above atmospheric pressure. This means that absolute pressure will always be higher than gauge pressure by the amount of atmospheric pressure at that location.

5. How does absolute pressure at different ocean depths affect organisms?

Organisms living in the ocean have adapted to the specific absolute pressure at their depth. Changes in pressure due to factors such as tides or storms can have a significant impact on their survival. Deep-sea organisms, for example, may have difficulty surviving if they are brought to the surface where the absolute pressure is much lower.

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