What is the Pressure and Resultant Force at the Bottom of the Tub?

AI Thread Summary
The discussion revolves around calculating the absolute pressure and resultant force at the bottom of a water-filled tub, which has specific dimensions. The initial calculations incorrectly used pressure values, but participants clarified that the absolute pressure should be calculated as 105,900 Pa, considering atmospheric pressure and water density. The resultant force was determined to be 4,900 Pa, but confusion arose regarding the terminology, as pressure is defined as force per area. Participants debated whether the resultant force should account for the dimensions of the tub, indicating the need for clarity in the problem's requirements. Overall, the conversation highlights the importance of understanding pressure and force relationships in fluid mechanics.
Newton86
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Homework Statement



( athmosphere pressure is normal 101 kPa)
A ”tub” has a form as a prism ( like on the pic ) with the following lengths
Length: 2m
Width : 0,75m
height: 0,5m
Whats the absolute pressure agains the sides at the bottom of the “tub” + resultant force

191143.jpe



Homework Equations



I Think
p=po + pgh


The Attempt at a Solution




(Im not sure about po and p )

For the absolute pressure I got :
P=Pa +pgh = 101 + 0,75*9,81*0,5 = 104,67 pa

And the resultant force
P = pgh = Resultantkraft: pgh = 0,75*9,81*0,5 = 3,675 pa
I have done something wrong haven't i ?
 
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Newton86 said:

Homework Statement



( athmosphere pressure is normal 101 kPa)
A ”tub” has a form as a prism ( like on the pic ) with the following lengths
Length: 2m
Width : 0,75m
height: 0,5m
Whats the absolute pressure agains the sides at the bottom of the “tub” + resultant force

191143.jpe



Homework Equations



I Think
p=po + pgh


The Attempt at a Solution




(Im not sure about po and p )

For the absolute pressure I got :
P=Pa +pgh = 101 + 0,75*9,81*0,5 = 104,67 pa

And the resultant force
P = pgh = Resultantkraft: pgh = 0,75*9,81*0,5 = 3,675 pa
I have done something wrong haven't i ?

Someone Please I am beggin here :smile:
 
Newton86 said:
( athmosphere pressure is normal 101 kPa)
A ”tub” has a form as a prism ( like on the pic ) with the following lengths
Length: 2m
Width : 0,75m
height: 0,5m
Whats the absolute pressure agains the sides at the bottom of the “tub” + resultant force

For the absolute pressure I got :
P=Pa +pgh = 101 + 0,75*9,81*0,5 = 104,67 pa

And the resultant force
P = pgh = Resultantkraft: pgh = 0,75*9,81*0,5 = 3,675 pa

Hi Newton86! :smile:

erm … what's the tub filled with? :confused:

and I don't think the width affects the pressure, does it? :smile:
 
Hi again Tim:smile::smile:
Its filled with water. And yeah you got a point with the width :-p

I think I have it now after I see what pa and P is.

absolute pressure:
Pa +pgh = 101000 + 1000kg/m^3*9,81*0,5 = 105900 pa

101kpa is 101000 pa and 1000kg/m^3 is the density of water.

Resultant force:

Resultantkraft: pgh = 1000kg/m^3*9,81*0,5 = 4900 pa

does this make sense ?
 
Hi Newton86! :smile:

Looks very good! :smile:

(But I don't understand what they mean by "resultant force" … 49000pa is a pressure … pressure = force/area … do they mean resultant-force/area? :confused:)​
 
Hi Newton86! :smile:

Looks very good! :smile:

(But I don't understand what they mean by "resultant force" … 49000pa is a pressure … pressure = force/area … do they mean resultant-force/area? :confused:)​
 
Dont ask me You are the smart one:wink:
But the resultant force to the bottom of the "tub"
I don't know but we got the information about length and width and so far i haven't used that info, maybe i should :confused:
 
Hi Newton86! :smile:

(hmm … sometimes they put in extra information just to test if you know what's relevant)

Is the question asking for the "resultant force at the bottom of the tub", or for the total resultant force on all the sides of the tub, right up to the top?
 
"The resultant force agains the bottom of the tub" I would say it also have info about a hatch but I think that is only relevant to the next question who is what the resultant force is agains the hatch..
 
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