A hydrometer is an instrument used to determine liquid density. Fluid of density p is drawn into the hydrometer, causing a rod of length L and known...

A hydrometer is an instrument used to determine liquid density. Fluid of density p is drawn into the hydrometer, causing a rod of length

L and known density po to partially float. A length ℎ of the rod protrudes above the surface of the liquid. Show that the density of the liquid is given p = poL / (L-h)