Question

For the du Noüy ring method, a ring, which is initially partially submerged in a liquid, is pulled slowly out of the liquid. If the material composing the ring is hydrophilic (the liquid adheres to the surface, forming a small contact angle between the liquid/vapor interface and the liquid/substrate interface), the ring will pull upward on the liquid as the ring is removed from the liquid. As with capillary action, this upward force is due to the cohesive forces of the liquid molecules pulling on each other at its surface. For the ring shown below, with outer radius Tout and inner radius Tin. what is the total length of the contact lines between the liquid's surface and the ring? ring.png O 27r(rin + rout) ○ 2m(Tout-rin) '11 Sprint 10:09 AM 65% ■ Exit Delow, wiL outer rauius out du inner radius rin, what is the total length of the contact lines between the liquid's surface and the ring? pull O 2m(rin Fout) out in O 2T(rout i) - in Previous Next

Answer 1