A police car is parked by the side of a highway and its siren emits a sound measuring 750 Hz. As you approach the police car fro
2 answers:
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Answer:
Explanation:
We know,
..............(1)
where,
η = Efficiency of the engine
T₁ = Initial Temperature
T₂ = Final Temperature
Q₁ = Heat available initially
Q₂ = Heat after reaching the temperature T₂
Given:
η =0.280
T₁ = 3.50×10² °C = 350°C = 350+273 = 623K
Q₁ = 3.78 × 10³ J
Substituting the values in the equation (1) we get
or
or
⇒
Now,
The entropy change () is given as:
or
substituting the values in the above equation we get
Answer:
x = 0.75801 = 75.801%
T_2 = 72..78 degree F
Explanation:
From superheated R 134 a properties table
At 200 lb/in^2 and 200 degree F
steady flow energy equation is givena s
At 90 lb/in2 Tsat = 72.78 degree F
hfg = 77.345 Btu/lbm
h = hf + x hfg
solving for x we get
x = 0.75801 = 75.801%