A portable compressor is taken from the place where the barometric pressure is 750 mm Hg and the average intake temperature is 27°C to a mountainous region where the barometric pressure is 560 mm Hg and temperature is 7°C. The reduction in mass output of the machine is:

Concept:

If the compressor is taken to different environment then the compressor volume remains constant but the density of the air changes, this change in density of the air will cause the change in mass output the compressor.

The density of the air is given by 

And the mass capacity of the compressor is given m = ρ × V

Where V is the volume of the compressor and P is the absolute pressure T is temperature of the air

Calculation:

Given, P₁ = 750 mm of hg, T₁ = 27°C = 300 K and P₂ = 560 mm of hg and T₂ = 7°C = 280 K

The density of the fluid in the compressor is given by-

Or, ρ₂ = 0.80 ρ₁

i.e. m₂ = 0.80 m₁ (As volume of compressor remain same)

So, % reduction 

⇒ % reduction (1 - 0.8) × 100 = 20%