Answer:
0.96kg/s
Explanation:
Hello! To solve this exercise we must use the first law of thermodynamics, which states that the sum of the energies that enter a system is the same amount that must go out. We must consider the following!
state 1 : is the first flow in the input of the chamber
h1=entalpy=335.02KJ/kg
m1=mass flow=0.56kg/s
state 2 : is the second flow in the input of the chamber
h2=entalpy=83.915KJ/kg
state 3:is the flow that comes out
h3=entalpy=175.90 kJ/kg
now use the continuity equation that states that the mass flow that enters is the same as the one that comes out
m1+m2=m3
now we use the first law of thermodynamics
m1h1+m2h2=m3h3
335.02m1+83.915m2=175.9m3
as the objective is to find the cold water mass flow(m2) we divide this equation by 175.9
1.9m1+0.477m2=m3
now we subtract the equations found in the equation of continuity and first law of thermodynamics
m1 + m2 = m3
-
1.9m1 + 0.477m2=m3
----------------------------------
-0.9m1+0.523m2=0
solving for m2
the mass flow rate of the cold-water is 0.96kg/s
Answer: 4I
Explanation:
If we had simply put in parallel with the wire one equal to it, the total current flowing through both resistors would double, due to the equivalent resistance of two resistors of equal value, in parallel, is just the half of one of them, so applying Ohm's Law, I will be double than I₀.
But in this case, everything happens as if we put in parallel two resistors of half the value (as the resistance is directly proportional to the length while Ohm's Law be valid), so the equivalent resistance becomes 1/4 of the original wire.
Applying Ohm's Law, we have I = (V / R/4) ⇒ I = 4 I₀
Answer:
The smallest radius at the junction between the cross section that can be used to transmit the torque is 0.167 inches.
Explanation:
Torsional shear stress is determined by the following expression:
Where:
- Torque, measured in 
.
- Radius of the cross section, measured in inches.
- Torsion module, measured in quartic inches.
- Torsional shear stress, measured in pounds per square inch.
The radius of the cross section and torsion module are, respectively:
Where 
is the diameter of the cross section, measured in inches.
Then, the shear stress formula is now expanded and simplified as a function of the cross section diameter:
In addition, diameter is cleared:
![D = 2\cdot \sqrt[3] {\frac {2\cdot T}{\pi\cdot \tau}}](https://tex.z-dn.net/?f=D%20%3D%202%5Ccdot%20%5Csqrt%5B3%5D%20%7B%5Cfrac%20%7B2%5Ccdot%20T%7D%7B%5Cpi%5Ccdot%20%5Ctau%7D%7D)
If 
and 
, then:
![D = \sqrt[3]{\frac{2\cdot (710\,lbf\cdot in)}{\pi \cdot (12000\,psi)} }](https://tex.z-dn.net/?f=D%20%3D%20%5Csqrt%5B3%5D%7B%5Cfrac%7B2%5Ccdot%20%28710%5C%2Clbf%5Ccdot%20in%29%7D%7B%5Cpi%20%5Ccdot%20%2812000%5C%2Cpsi%29%7D%20%7D)
The smallest radius at the junction between the cross section that can be used to transmit the torque is 0.167 inches.
Answer:
The government would have less power to control the cost of electricity from privately funded projects.
Explanation:
According to the given excerpt, the government, the government decided to take over most of the hydroelectric power projects as opposed to privately owned corporations which previously held a monopoly. The major reason was to provide low-cost energy to consumers.
This decision taken by the government to use the Army Corps of Engineers to undertake hydroelectric power projects instead of allowing private businesses to undertake them was to allow the government have more power to control the cost of electricity.
