Fluid pressure physics homework

[jason_r]

A 0.800 m-diameter vat of liquid is 2.70 m deep. The pressure at the bottom of the vat is 1.20 atm.

What is the mass of the liquid in the vat?

 

[tiny-tim]

Welcome to PF!

A 0.800 m-diameter vat of liquid is 2.70 m deep. The pressure at the bottom of the vat is 1.20 atm.

What is the mass of the liquid in the vat?

Hi jason_r! Welcome to PF!

Show us what you've tried, and where you're stuck, and then we'll know how to help.

Hint: find the density first.

 

[jason_r]

Hi jason_r! Welcome to PF!

Show us what you've tried, and where you're stuck, and then we'll know how to help.

Hint: find the density first.

so far i have :

PA=P_oA +mg
(1215600)(pi*(0.4)^2)= (1.013x10^5)(pi(0.4)^2) + 9.8m
m=1.04 x 10^4kg

I need confirmation on the answer and if I am doing this right
cause i don't have a key or anything
thanks

 

[tiny-tim]

PA=P_oA +mg
(1215600)(pi*(0.4)^2)= (1.013x10^5)(pi(0.4)^2) + 9.8m
m=1.04 x 10^4kg

Yes, that's fine:

(I haven't checked your value for 1 atm … and I'm assuming you meant 10^6, so that it matches the 1215600)

You've used a force equation … force on the bottom minus force on the top = weight … P_-A - P₊A = mg.

You could also have use the pressure equation (that's the one I'd have used): P_- - P₊ = rho gh.

But they both give the same result, and they're both fine.