One annular metal ring of inner radius 7 cm and outer radius 14 cm and negligible weight is floating on the surface of a liquid. If surface tension of liquid is 0.08Nm^(-1), calculate the force required to detach it from liquid surface.

One annular metal ring of inner radius 7 cm and outer radius 14 cm and

1.	One annular metal ring of inner radius 7 cm and outer radius 14 cm and negligible weight is floating on the surface of a liquid. If surface tension of liquid is 0.08Nm^(-1), calculate the force required to detach it from liquid surface.
Answer» Solution :The CONTACT length of annular ring with liquid surface `L=2pir_(1)+2pir_(2)""L=2xx(22)/(7)xx(14+7)cm` `L=132cm=1.32m` The force required, `F=S(L)=0.08xx1.32` `F=0.1056N`.