Given Information:
Inlet Temperature of hot air= Th₁ = 450K
Exit Temperature of hot air = Th₂ = 350K
Inlet Temperature of cold air = Tc₁ = 300K
Volume flow rate of hot air = vh = 0.02 m³/s
Volume flow rate of cold air = vc = 1 m³/s
Required Information:
Exit Temperature of cold air= Tc₂ = ?
Answer:
Exit Temperature of cold air = Tc₂ = 302 °C
Explanation:
In a heat exchanger, the cold air absorbs heat that is lost by the hot air,
Heat absorbed by cold air = Heat lost by hot air
![m_{c}\cdot c_{p}(T_{c2} -T_{c1} ) = m_{h}\cdot c_{p}(T_{h1} -T_{h2})\\m_{c}(T_{c2} -T_{c1} ) = m_{h}(T_{h1} -T_{h2})\\\rho\dot{v_{c}}(T_{c2} -T_{c1} ) =\rho\dot{v_{h}} (T_{h1} -T_{h2})\\\dot{v_{c}}(T_{c2} -T_{c1} ) =\dot{v_{h}} (T_{h1} -T_{h2})\\1 \cdot(T_{c2} -300 ) =0.02\cdot (450 -350)\\(T_{c2} -300 ) =0.02\cdot (100)\\(T_{c2} -300 ) =2\\T_{c2} =2 + 300 \\T_{c2} = 302](https://tex.z-dn.net/?f=m_%7Bc%7D%5Ccdot%20c_%7Bp%7D%28T_%7Bc2%7D%20-T_%7Bc1%7D%20%29%20%3D%20m_%7Bh%7D%5Ccdot%20c_%7Bp%7D%28T_%7Bh1%7D%20-T_%7Bh2%7D%29%5C%5Cm_%7Bc%7D%28T_%7Bc2%7D%20-T_%7Bc1%7D%20%29%20%3D%20m_%7Bh%7D%28T_%7Bh1%7D%20-T_%7Bh2%7D%29%5C%5C%5Crho%5Cdot%7Bv_%7Bc%7D%7D%28T_%7Bc2%7D%20-T_%7Bc1%7D%20%29%20%3D%5Crho%5Cdot%7Bv_%7Bh%7D%7D%20%28T_%7Bh1%7D%20-T_%7Bh2%7D%29%5C%5C%5Cdot%7Bv_%7Bc%7D%7D%28T_%7Bc2%7D%20-T_%7Bc1%7D%20%29%20%3D%5Cdot%7Bv_%7Bh%7D%7D%20%28T_%7Bh1%7D%20-T_%7Bh2%7D%29%5C%5C1%20%5Ccdot%28T_%7Bc2%7D%20-300%20%29%20%3D0.02%5Ccdot%20%28450%20-350%29%5C%5C%28T_%7Bc2%7D%20-300%20%29%20%3D0.02%5Ccdot%20%28100%29%5C%5C%28T_%7Bc2%7D%20-300%20%29%20%3D2%5C%5CT_%7Bc2%7D%20%20%3D2%20%2B%20300%20%5C%5CT_%7Bc2%7D%20%20%3D%20302)
Therefore, the exit temperature of the cold air is 302 °C or 575K
Note:
m = ρv
Where ρ is density of air and v is the volume flow rate and m is the mass flow rate.
cp is the specific heat capacity of air.
Conserved
Explanation:
The first law of thermodynamics states that energy in a systems is "conserved".
This law is the law of conservation of energy of energy. It states that:
"in an isolated system, energy can neither be created nor destroyed but it is transformed from one form to another".
- This simply shows that energy is conserved in an isolated system.
- In an isolated system, there is no exchange of energy with the environment.
- Also, energy is neither formed nor destroyed but transformed.
Learn more:
Conservation of matter brainly.com/question/2190120
#learnwithBrainly
Answer:
Part a)
a = 1.62 m/s/s
Part b)
a = 3.70 m/s/s
Explanation:
Part A)
Acceleration due to gravity on the surface of moon is given as
![a = \frac{GM}{R^2}](https://tex.z-dn.net/?f=a%20%3D%20%5Cfrac%7BGM%7D%7BR%5E2%7D)
here we know that
![M = 7.35 \times 10^{22} kg](https://tex.z-dn.net/?f=M%20%3D%207.35%20%5Ctimes%2010%5E%7B22%7D%20kg)
![R = 1.74 \times 10^6 m](https://tex.z-dn.net/?f=R%20%3D%201.74%20%5Ctimes%2010%5E6%20m)
now we have
![a_g = \frac{(6.67 \times 10^{-11})(7.35 \times 10^{22})}{(1.74 \times 10^6)^2}](https://tex.z-dn.net/?f=a_g%20%3D%20%5Cfrac%7B%286.67%20%5Ctimes%2010%5E%7B-11%7D%29%287.35%20%5Ctimes%2010%5E%7B22%7D%29%7D%7B%281.74%20%5Ctimes%2010%5E6%29%5E2%7D)
![a_g = 1.62 m/s^2](https://tex.z-dn.net/?f=a_g%20%3D%201.62%20m%2Fs%5E2)
Part B)
Acceleration due to gravity on surface of Mercury is given as
![a = \frac{GM}{R^2}](https://tex.z-dn.net/?f=a%20%3D%20%5Cfrac%7BGM%7D%7BR%5E2%7D)
here we know that
![M = 3.30 \times 10^{23} kg](https://tex.z-dn.net/?f=M%20%3D%203.30%20%5Ctimes%2010%5E%7B23%7D%20kg)
![R = 2.44 \times 10^6 m](https://tex.z-dn.net/?f=R%20%3D%202.44%20%5Ctimes%2010%5E6%20m)
now we have
![a_g = \frac{(6.67 \times 10^{-11})(3.30 \times 10^{23})}{(2.44 \times 10^6)^2}](https://tex.z-dn.net/?f=a_g%20%3D%20%5Cfrac%7B%286.67%20%5Ctimes%2010%5E%7B-11%7D%29%283.30%20%5Ctimes%2010%5E%7B23%7D%29%7D%7B%282.44%20%5Ctimes%2010%5E6%29%5E2%7D)
![a_g = 3.70 m/s^2](https://tex.z-dn.net/?f=a_g%20%3D%203.70%20m%2Fs%5E2)
Conservation means to improve something to prevent loss or decay
That's why energy can't be created or destroyed