A bird of mass 1.23 kg is able to hover by imparting a downward velocity of \(10 ms^{-1}\) uniformly to air of density \(\rho kg-m^{-3}\) over an effective area \(0.1 m^2\). If the acceleration due to gravity is \(10 ms^{-2}\) then the magnitude of \(\rho\) is in \(kg-m^{-3}\)