Flow through a Venturi tube, a Venturi tube, with a throat 3 in. in diameter, is placed in a circular pipe I ft in diameter carrying dry air. The discharge coefficient C_d of the meter is 0.98. Calculate the mass flow rate of air in the pipe if the air enters the Venturi at 70°F and 1atm and the throat pressure is 0.75atm. 

(a) Assume adiabatic frictionless flow and γ = 1.4. 

(b) Assume isothermal flow. 

(c) Assume incompressible flow at the entering density.