How Do SI Units Affect Calculations in Fluid Statics?

[clueless8]

Homework Statement

I'm having trouble getting the correct answer on two problems within one and I don't know where I'm going wrong. I will go to my T.As during the week but I would rather finish my homework this weekend.

The question is If you were to dive down 12.5m below surface level, what is
1. The pressure due to water alone?
2.The total or absolute pressure at depth given atmospheric pressure = 1.01E5 N/m^2

Relevant Equations

P = hpg
Ptotal = Pgauge + Patm

For A) I used P = hpg (h=0.0125km, p=1000kg/m^3, and g= 9.8m/s^2) this gave me 122.5N/m^2
For B) I used Ptotal = Pgauge + Patm
= 1.01E5 + 122.5 = 101122.5 N/m^2

 

[haruspex]

Homework Statement: I'm having trouble getting the correct answer on two problems within one and I don't know where I'm going wrong. I will go to my T.As during the week but I would rather finish my homework this weekend.

The question is If you were to dive down 12.5m below surface level, what is
1. The pressure due to water alone?
2.The total or absolute pressure at depth given atmospheric pressure = 1.01E5 N/m^2
Relevant Equations: P = hpg
Ptotal = Pgauge + Patm

For A) I used P = hpg (h=0.0125km, p=1000kg/m^3, and g= 9.8m/s^2) this gave me 122.5N/m^2
For B) I used Ptotal = Pgauge + Patm
= 1.01E5 + 122.5 = 101122.5 N/m^2

Why did you convert to km?

 

[Lnewqban]

Welcome!

1 Pascal = Force of 1 Newton per square meter
Atmospheric pressure at sea level = 101,325 Pascals = 760 mm Hg = 760 torr = 14.7 psi = 1 atm

 

[haruspex]

Welcome!

1 Pascal = Force of 1 Newton per square meter
Atmospheric pressure at sea level = 101,325 Pascals = 760 mm Hg = 760 torr = 14.7 psi = 1 atm

The valuel of atmospheric pressure to use is given.

 

[Orodruin]

For A) I used P = hpg (h=0.0125km, p=1000kg/m^3, and g= 9.8m/s^2) this gave me 122.5N/m^2

Check your units!

 

[clueless8]

Why did you convert to km?

I have trouble in this area, I assumed I had to due because the final answer asks for N/m^2 so I thought it had to be in km due to SI units , should I stick with 12.5m ?

 

[Orodruin]

I have trouble in this area, I assumed I had to due because the final answer asks for N/m^2 so I thought it had to be in km due to SI units , should I stick with 12.5m ?

The SI base unit of length is 1 m, not 1 km. The derived unit of newton is 1 N = 1 kg m/s², not a km to be seen anywhere. The only ”k” in there is in kg, the SI base unit for mass.