# Homework Help: Basic Surface Tension Problem

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1. Nov 7, 2014

### EmilyO89

1.
Calculate the force needed to move the wire in the figure (Figure 1) if it holds a soapy solution (surface tension is 0.025 N/m) and the wire is 16.0 cm long.

Express your answer to two significant figures and include the appropriate units.

2.

γ(surface tension) = F (force) / l (length)

3. My attempt at a solution

γ=F/l so γl=F

γ: 0.025 N/m

l: 16cm or 0.16m

0.025 N/m * 0.16m = 0.004 N or 4.0 * 10-3N

I know this must be ridiculously easy but I really can't figure out what I'm missing here. Do I need another equation to solve this problem? Am I messing up the units somehow?

2. Nov 7, 2014

### RonL

I can't help at this time, but someone will pretty soon:) I just have time to say welcome to PF and hope you stay around and get to know some people:D

3. Nov 7, 2014

### Staff: Mentor

Look very carefully at the second part of the figure.

Chet

4. Nov 7, 2014

### EmilyO89

Got it. Thank you!

I knew it must be something simple like that but I was getting hung up because I just could not visualize exactly what this thing is supposed to look like.

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