Pressure, Density, and Atmospheric Pressure

[kallisti]

Homework Statement

What is the absolute (total) pressure at the depth of 15 m below the surface of the sea. Assume density of seawater is 1.03 g/cm3 and g=10 m/s2. Give answer in kPa. Use atmospheric pressure is 101 kPa.

Homework Equations

P = F/A
P₁V₁=P₂V₂

The Attempt at a Solution

i don't know how to solve it because neither of the formulae my teacher gave me have atmostpheric pressure or density and the problem doesn't have volume please help!

 

[jonwell]

Pressure in this case doesn't depend on volume, it just depends on gravity, density and the height of the fluid column above you. You've probably seen the equation before- p=d*g*h.

The total, then, is just that plus atmospheric pressure.

 

[thomate1]

As a scientist, it is important to understand and apply the relevant equations and principles to solve problems. In this case, we can use the equation P = ρgh, where P is the absolute pressure, ρ is the density of the fluid (seawater in this case), g is the acceleration due to gravity, and h is the depth. We can rearrange this equation to solve for P:

P = ρgh = (1.03 g/cm3)(10 m/s2)(15 m) = 154.5 kPa

However, this answer only gives us the gauge pressure, which is the pressure above atmospheric pressure. To find the absolute pressure, we need to add the atmospheric pressure to this value:

Pabsolute = P + Patm = 154.5 kPa + 101 kPa = 255.5 kPa

Therefore, the total absolute pressure at a depth of 15 m below the surface of the sea is 255.5 kPa. It is important to note that the density of seawater and the acceleration due to gravity were given in the problem, and the atmospheric pressure was provided as a reference value to add to the gauge pressure. It is also important to remember to use consistent units in calculations, so the density of seawater should be converted to kg/m3 to match the units of g.

I hope this helps you understand how to approach and solve this problem. Remember to always carefully read and understand the given information and use the appropriate equations to solve the problem.