Physics - Fluid Question with Solution | TestHub

The weight of the disc is balanced by the force due to the surface tension and the upthrust of water. The component of surface tension in vertically upward direction is $\mathrm{T}\cos \theta$ and the force acting due to it $2\pi \mathrm{rT}\cos \theta$. The upthrust is equal to the weight of the water displaced (W). $\therefore$ Weight of the disc $=2\pi \mathrm{rT}\cos \theta +\mathrm{W}$