Arigid, well-insulated tank of volume 0.9 m is initially evacuated. at time t = 0, air from the surroundings at 1 bar, 27°c begins to flow into the tank. an electric resistor transfers energy to the air in the tank at a constant rate for 5 minutes, after which time the pressure in the tank is 1 bar and the temperature is 457°c. modeling air as an ideal gas, determine the power input to the tank, in kw.

= -0.303 KW

Explanation:

This is the case of unsteady flow process because properties are changing with time.

From first law of thermodynamics for unsteady flow process

Given that tank is insulated so and no mass is leaving so

Mass conservation

is the initial and final mass in the system respectively.

Initially tank is evacuated so

We know that for air ,

So now putting values

= -0.303 KW

answer:

put more,

answer:

what work

explanation: