Answer:
h = 375 KW/m^2K
Explanation:
Given:
Thermo-couple distances: L_1 = 10 mm , L_2 = 20 mm
steel thermal conductivity k = 15 W / mK
Thermo-couple temperature measurements: T_1 = 50 C , T_2 = 40 C
Air Temp T_∞ = 100 C
Assuming there are no other energy sources, energy balance equation is:
E_in = E_out
q"_cond = q"_conv
Since, its a case 1-D steady state conduction, the total heat transfer rate can be found from Fourier's Law for surfaces 1 and 2
q"_cond = k * (T_1 - T_2) / (L_2 - L_1) = 15 * (50 - 40) / (0.02 - 0.01)
=15KW/m^2
Assuming SS is solid, temperature at the surface exposed to air will be 60 C since its gradient is linear in the case of conduction, and there are two temperatures given in the problem. Convection coefficient can be found from Newton's Law of cooling:
q"_conv = h * ( T_∞ - T_s ) ----> h = q"_conv / ( T_∞ - T_s )
h = 15000 W / (100 - 60 ) C = 375 KW/m^2K
Answer:
The warming causes the oceans to release CO2. The CO2 amplifies the warming and mixes through the atmosphere, spreading warming throughout the planet. So CO2 causes warming AND rising temperature causes CO2 rise. Overall, about 90% of the global warming occurs after the CO2 increase.
Explanation:
Answer:
a). Work transfer = 527.2 kJ
b). Heat Transfer = 197.7 kJ
Explanation:
Given:
= 5 Mpa
= 1623°C
= 1896 K
= 0.05 ![m^{3}](https://tex.z-dn.net/?f=m%5E%7B3%7D)
Also given ![\frac{V_{2}}{V_{1}} = 20](https://tex.z-dn.net/?f=%5Cfrac%7BV_%7B2%7D%7D%7BV_%7B1%7D%7D%20%3D%2020)
Therefore,
= 1 ![m^{3}](https://tex.z-dn.net/?f=m%5E%7B3%7D)
R = 0.27 kJ / kg-K
= 0.8 kJ / kg-K
Also given : ![P_{1}V_{1}^{1.25}=C](https://tex.z-dn.net/?f=P_%7B1%7DV_%7B1%7D%5E%7B1.25%7D%3DC)
Therefore,
= ![P_{2}V_{2}^{1.25}](https://tex.z-dn.net/?f=P_%7B2%7DV_%7B2%7D%5E%7B1.25%7D)
![5\times 0.05^{1.25}=P_{2}\times 1^{1.25}](https://tex.z-dn.net/?f=5%5Ctimes%200.05%5E%7B1.25%7D%3DP_%7B2%7D%5Ctimes%201%5E%7B1.25%7D)
= 0.1182 MPa
a). Work transfer, δW = ![\frac{P_{1}V_{1}-P_{2}V_{2}}{n-1}](https://tex.z-dn.net/?f=%5Cfrac%7BP_%7B1%7DV_%7B1%7D-P_%7B2%7DV_%7B2%7D%7D%7Bn-1%7D)
![\left [\frac{5\times 0.05-0.1182\times 1}{1.25-1} \right ]\times 10^{6}](https://tex.z-dn.net/?f=%5Cleft%20%5B%5Cfrac%7B5%5Ctimes%200.05-0.1182%5Ctimes%201%7D%7B1.25-1%7D%20%20%5Cright%20%5D%5Ctimes%2010%5E%7B6%7D)
= 527200 J
= 527.200 kJ
b). From 1st law of thermodynamics,
Heat transfer, δQ = ΔU+δW
= ![\frac{mR(T_{2}-T_{1})}{\gamma -1}+ \frac{P_{1}V_{1}-P_{2}V_{2}}{n-1}](https://tex.z-dn.net/?f=%5Cfrac%7BmR%28T_%7B2%7D-T_%7B1%7D%29%7D%7B%5Cgamma%20-1%7D%2B%20%5Cfrac%7BP_%7B1%7DV_%7B1%7D-P_%7B2%7DV_%7B2%7D%7D%7Bn-1%7D)
=![\left [ \frac{\gamma -n}{\gamma -1} \right ]\times \delta W](https://tex.z-dn.net/?f=%5Cleft%20%5B%20%5Cfrac%7B%5Cgamma%20-n%7D%7B%5Cgamma%20-1%7D%20%5Cright%20%5D%5Ctimes%20%5Cdelta%20W)
=![\left [ \frac{1.4 -1.25}{1.4 -1} \right ]\times 527.200](https://tex.z-dn.net/?f=%5Cleft%20%5B%20%5Cfrac%7B1.4%20-1.25%7D%7B1.4%20-1%7D%20%5Cright%20%5D%5Ctimes%20527.200)
= 197.7 kJ
Answer:
7.9 kilometers per second
Explanation:
Answer:
Zoning is like a hammer because it is used as a tool for urban planning.