In the device for measuring surface tension shown in Figure 18. 58 , the length of the

Question:

In the device for measuring surface tension shown in Figure 18. 58 , the length of the movable wire is \(\ell\). When the film holding the wire in place is water at \(20^{\circ} \mathrm{C}\), you must do \(1.46 \mu \mathrm{J}\) of work on the wire to move it a distance \(\Delta x\) downward. If the film were instead mercury at the same temperature, how much work would be required to move the wire a distance \(\Delta x / 2\) ? The surface tensions at \(20^{\circ} \mathrm{C}\) are \(7.28 \times 10^{-2} \mathrm{~N} / \mathrm{m}\) for water and \(0.465 \mathrm{~N} / \mathrm{m}\) for mercury.

Data from Figure 18.58

image text in transcribed