Air enters a nozzle steadily at 2.21 kg/m3 and 40 m/s and leaves at 0.752 kg/m3 and 180 m/s. If the inlet area of the nozzle is 90 cm2, determine (a) the mass flow rate through the nozzle, and (b) the exit area of the nozzle.

(a) 0.796 kg/s,
(b) 58 cm2

Answer

Given,

Air enter density, ρ₁ = 2.21 kg/m³

speed of entry, v₁ = 40 m/s

Air exit density , ρ₂ = 0.752 kg/m³

speed of exit, v₂ = 180 m/s

Inlet area = 90 cm²

a) mass flow rate through nozzle.

            m = 0.796 kg/s

b) exit area

  Using continuity equation

Exit area of nozzle is equal to

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.