A cylindrical iron rod 8cm height and 6cm in diameter stands in a cylindrical tin 12cm in diameter water is poured into the tin unfit it's depth is 8cm how far until the level drop when the rod is removed
the volume of water displaced by the rod is
v = πr^2 h = π * 3^2 * 8 = 72π cm^3
The drop in water level is the rod volume divided by the cross-section area of the tin, or
72π/(π*6^2) = 2 cm