What is the mass of the water in the stirrer supported by surface tension?

AI Thread Summary
The discussion centers on calculating the mass of water supported by surface tension in a hollow stirrer with a diameter of 2.0 mm. The relevant equations involve surface tension and pressure, specifically deltaP=2y/r and deltaP=F/A. The user initially struggles with the calculations but ultimately realizes a minor mistake in their work. After correcting the error, they confirm they arrived at the correct answer. The conversation highlights the importance of careful calculations in physics problems.
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Homework Statement


A hollow stirrer that has a diameter of 2.0 mm is inserted into a cup of water at 20∘C. The surface tension of water at that temperature is γ(surface tension) = 7.28×10−2 N/m.

What is the mass of the water supported by the surface tension in the stirrer?

Given:
d=2 mm
p(rho): 1000 kg/m^3
y(surface tension): 7.28E-2 N/m

Find: Mass

Conversions:
d=.002 m r=.001

Problem: I tried this equation, but I keep on getting the wrong answer, I am not sure if I am using the correct formula.

Homework Equations


Surface tension: deltaP=2y/r
Pressure: deltaP=F/A

The Attempt at a Solution


detlaP=2y/r
deltaP=F/A
F=mg
A=(pi)r^2
Plug them in:
mg/(pi)r^2=2y/r
Change the equation to equal mass (m):
m=2y(pi)r/g
 
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Your work looks good. What numerical answer did you get for m?
 
TSny said:
Your work looks good. What numerical answer did you get for m?
Nevermind, I got the right answer just a minor mistake. Sorry about that. Thanks for the help!
 
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