Answer:
79 kW.
Explanation:
The equation for enthalpy is:
H2 = H1 + Q - L
Enthalpy is defined as:
H = G*(Cv*T + p*v)
This is specific volume.
The gas state equation is:
p*v = R*T (with specific volume)
The specific gas constant for air is:
287 K/(kg*K)
Then:
T1 = 60 + 273 = 333 K
T2 = 200 + 273 = 473 K
p1*v1 = 287 * 333 = 95.6 kJ/kg
p2*v2 = 287 * 473 = 135.7 kJ/kg
The Cv for air is:
Cv = 720 J/(kg*K)
So the enthalpies are:
H1 = 0.8*(0.72 * 333 + 95.6) = 268 kW
H2 = 0.8*(0.72 * 473 + 135.7) = 381 kW
Ang the heat is:
Q = 34 kW
Then:
H2 = H1 + Q - L
381 = 268 + 34 - L
L = 268 + 34 - 381 = -79 kW
This is the work from the point of view of the air, that's why it is negative.
From the point of view of the machine it is positive.
It is uncommon for electrocution to cause crane incidents: False.
<h3>What is
electrocution?</h3>
Electrocution can be defined as a process through which a certain amount of electric current (electricity) passes through the body of a living organism, thereby, leading to death or severe injury.
According to the occupational safety and health administration (OSHA), it is very common for electrocution to cause crane incidents and accidents when adequate safety precautions are not adopted.
Read more on OSHA here: brainly.com/question/17199752
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Answer:
The work required is W = 20.2 BTU per lbm
Explanation:
The value of entropy & enthalpy at initial conditions are
= 103.1
S = 0.225
Final enthalpy
= 123.3
Therefore work done
W = -
W = 103.1 - 123.3
W = - 20.2 BTU per lbm
Therefore the work required is W = 20.2 BTU per lbm
