- #1
FaraDazed
- 347
- 2
This is not homework or coursework. I have an exam coming up and this question is from a past paper and I am unsure why but it is confusing me a bit.
A cube of side 0.3m which has an average density of 4500 kg/m^3 . Determine the overall force acting on the cube when it is submerged in water.
Density of water is given to be 1000 kg/m^3
[itex]
p=h \rho g \\
[/itex]
Upthrust = [itex] \rho g V = \rho g l^3 [/itex]
The main reason I am confused is because I thought one would need to know the depth, h, the cube is submerged at?
I understand that one only needs to consider the forces acting on the top face and bottom face because the others cancel out but again, I have no idea how I am supposed to do that without knowing the depth.
Is it simply that the total force is equal to the upthrust? Because that's the only equation I can think of that does not include the depth.
If so then it is simply
[itex] \rho g l^3 = 4500 \times 9.81 \times 0.3^3 = 1192 N [/itex]
Also, is there a symbol used to represent upthrust or is it simply something like F with a subscript?
Any help appreciated. Thanks :)
Homework Statement
A cube of side 0.3m which has an average density of 4500 kg/m^3 . Determine the overall force acting on the cube when it is submerged in water.
Density of water is given to be 1000 kg/m^3
Homework Equations
[itex]
p=h \rho g \\
[/itex]
Upthrust = [itex] \rho g V = \rho g l^3 [/itex]
The Attempt at a Solution
The main reason I am confused is because I thought one would need to know the depth, h, the cube is submerged at?
I understand that one only needs to consider the forces acting on the top face and bottom face because the others cancel out but again, I have no idea how I am supposed to do that without knowing the depth.
Is it simply that the total force is equal to the upthrust? Because that's the only equation I can think of that does not include the depth.
If so then it is simply
[itex] \rho g l^3 = 4500 \times 9.81 \times 0.3^3 = 1192 N [/itex]
Also, is there a symbol used to represent upthrust or is it simply something like F with a subscript?
Any help appreciated. Thanks :)