Engineering Fluids mechanics homework, feel like I have messed up the equations

AI Thread Summary
The discussion revolves around confusion regarding the coefficient of viscosity and its application in fluid mechanics equations. The user seeks guidance on how to calculate the coefficient of viscosity and whether to use only part of equation 3 or combine both sides to find dynamic viscosity. They have shared images of their work, including equations and practical data, but express uncertainty about progressing with the correct values. A participant points out a typo in equation 3, noting that dynamic viscosity is incorrectly placed in the denominator. The user appreciates the feedback and has updated their post with additional images for clarity.
Meckii
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Homework Statement
Confused with trying to find the values in the equation although I feel like im just messing up the equation in my head.
Relevant Equations
Equation 3: Coefficient of viscosity = 4 x pi x r^3 × g / 3 x 6 x pi x coefficient of visc x mean velocity of ball
(Ps - P1) = (2/9) x r^2 x g ((ps - p1) / u)

Equation 5: v = dynamic viscosity / density
Edit: So I have written out equation 3 again and taken a picture to show my working out, the 2 things that I am confused about is how do I find the coefficient of viscosity? I know that syrup is high viscosity and water is low viscosity but I don't know the equation to get the actual value. The 2nd issue I have is when I have the coefficient of viscosity value, do I just use the 1st part of equation 3 to find the Dynamic Viscosity or do I have to somehow combine both sides of the equation? If it is the latter I do not have a clue how to work out both together. The last 2 images are what I have worked out just.

I have attempted my solution on the images attached, the first 3 images show the equations needed for the questions while the last 4 or 5 images show my working out and the way I tried attempting the questions.

The 4th pic shows the practical work done showing the specific gravity, s and the Density, p. While the 6th page shows my attempt at the equation 3 and equation 5, the final page shows equation 5 questions at the top also. While in the 5th pic the times that the ball took to travel a certain distance is shown at the top.

All I really ask is a little bit of guidance as it has stumped me quite a bit and I am unsure how to progress with the correct values/answers.

Values achieved,
s = shown in the first table
Density, p = shown in the 2nd table
u = mean average is shown in last pic
g = 9.81
Ps = 7.850 (I am assuming this is correct, density of steel which I looked up)
P1 = given in the density table on page 4, all 4 values
r = the radius which is known as 1.59mm, 2.38mm and 3.175mm
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Last edited:
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Lnewqban said:
Equation #3 has a typo, as it incorrectly includes the dynamic viscosity (μ) in the denominator.
Please, see:
https://en.m.wikipedia.org/wiki/Stokes'_law

Welcome, Meckii :cool:
Lnewqban said:
Equation #3 has a typo, as it incorrectly includes the dynamic viscosity (μ) in the denominator.
Please, see:
https://en.m.wikipedia.org/wiki/Stokes'_law

Welcome, Meckii :cool:
Updated, surprised i missed that, thanks for letting me know though, ended up forgetting to add the pics also
 
Edit: I pictures 4-6 are the first pictures added, pictures 7-8 are the new pictures I have added which I just wrote out.
 

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