Chapter 10, Problem 60P

To determine

The force needed to move the wire, is to be determined.

Answer to Problem 60P

The force needed to move the wire is $9.1\times {10}^{-3}N$ .

Explanation of Solution

Given info:

Surface tension, $\gamma =2.5\times {10}^{-2}N/m$

  $L=18.2cm=0.182m$

Formula used:

The surface tension formula for a U-shaped wire apparatus is,

  $\gamma =\frac{F}{2L}$

Calculation:

Substitute the value of the force and length in the given formula,

  $\begin{array}{l}\gamma =\frac{F}{2L}\\ F=\gamma 2L\\ =0.182m\times 2\times 2.5\times {10}^{-2}\\ =9.1\times {10}^{-3}N\end{array}$

Conclusion:

The force needed to move the wire is $9.1\times {10}^{-3}N$ .