Fluid mechanics - is there enough information for this problem?

AI Thread Summary
The discussion centers on a fluid mechanics homework problem that lacks critical information, particularly regarding densities and the cross-sectional area for the outlet. The user expresses frustration over the teaching assistant's tendency to omit essential details, making it challenging to solve for velocity. They outline their approach using conservation of linear momentum and mass flow, highlighting the presence of multiple unknowns in the equations. The user considers assuming equal densities for simplification but finds that it does not significantly aid in solving the problem. Overall, the lack of provided data complicates the application of fundamental fluid mechanics principles.
pyroknife
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Attached the problem.

The TA for my class makes up all the damn homework problems, but she has a habit of leaving out important information on every single homework assignment. Sorry for the rant, just had to vent a bit.

Unless they want all this in variables, I don't see a way to get a # for the velocity. We're not given any densities...am i supposed to assume that the density for both inlets are the same?
Cross section for the exit is not given...my approach was to use the conservation of linear momentum
as stated in the problem, the horizontal and vertical forces are 0.

m'=mass flow (kg/s)
m'1=mass flow at inlet 1
m'2=mass flow at inlet 2
m'3=mass flow at outlet 3
V1=velocity1
Sum of forces in the x gives: m'1*V1=(m'1+m'2)*V3*cos(theta)
sum of forces in the y gives: m'2*V2=(m'1+m'2)*V3*sin(theta) << solving this equation for V3 and substituting back into other equation gives
m'1*V1=m'2*V2*cos(theta)/sin(theta)

That's 3 unknowns

I guess I can do CONSERVATION of mass flow as well

m'1+m'2=m'3
density1*Area1*velocity1+density2*area2*velocity2=density3*area*3*velocity*3
This doesn't really help me at all.
 

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Assuming the densities are the same, separately equate the forces in the x and y directions. For instance:

Q1 * V1 = Q3 * V3 * cos(theta)

where Q = V * A

so

A1 * V1^2 = A3 * V3^2 * cos(theta)

etc...
 
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