Answer:
Time required for iron rod surface temperature to cool to 200°C is 250 seconds.
Explanation:
Answer:
Fatigue factor of safety is 2.0267
Explanation:
Solution is attached below.
Answer:
Heat losses by convection, Qconv = 90W
Heat losses by radiation, Qrad = 5.814W
Explanation:
Heat transfer is defined as the transfer of heat from the heat surface to the object that needs to be heated. There are three types which are:
1. Radiation
2. Conduction
3. Convection
Convection is defined as the transfer of heat through the actual movement of the molecules.
Qconv = hA(Temp.final - Temp.surr)
Where h = 6.4KW/m2K
A, area of a square = L2
= (0.25)2
= 0.0625m2
Temp.final = 250°C
Temp.surr = 25°C
Q = 64 * 0.0625 * (250 - 25)
= 90W
Radiation is a heat transfer method that does not rely upon the contact between the initial heat source and the object to be heated, it can be called thermal radiation.
Qrad = E*S*(Temp.final4 - Temp.surr4)
Where E = emissivity of the surface
S = boltzmann constant
= 5.6703 x 10-8 W/m2K4
Qrad = 5.6703 x 10-8 * 0.42 * 0.0625 * ((250)4 - (25)4)
= 5.814 W
Answer:44.61 KJ
Explanation:
Let h_1,V_1,Z_1 be the initial specific enthalpy,velocity&elevation of the system
and h_2,V_2,Z_2 be the Final specific enthalpy,velocity&elevation of the system
mass(m)=7kg
Applying Steady Flow Energy Equation
![m\left [ h_1+\frac{v_1^2}{2g}+gZ_1\right ]](https://tex.z-dn.net/?f=m%5Cleft%20%5B%20h_1%2B%5Cfrac%7Bv_1%5E2%7D%7B2g%7D%2BgZ_1%5Cright%20%5D)
+Q=![\left [ h_2+\frac{v_2^2}{2g}+gZ_2\right ]](https://tex.z-dn.net/?f=%5Cleft%20%5B%20h_2%2B%5Cfrac%7Bv_2%5E2%7D%7B2g%7D%2BgZ_2%5Cright%20%5D)
+W
substituting values
![7\left [ h_1+\frac{13^{2}}{2g}+gZ_1\right ]+7\times2](https://tex.z-dn.net/?f=7%5Cleft%20%5B%20h_1%2B%5Cfrac%7B13%5E%7B2%7D%7D%7B2g%7D%2BgZ_1%5Cright%20%5D%2B7%5Ctimes2)
= ![\left [ h_2+\frac{23^2}{2g}+gZ_2\right ]](https://tex.z-dn.net/?f=%5Cleft%20%5B%20h_2%2B%5Cfrac%7B23%5E2%7D%7B2g%7D%2BgZ_2%5Cright%20%5D)
+W
W=![7\left [h_1-h_2+\frac{V_1^2-V_2^2}{2000g}+g\frac{\left (Z_1-Z_2 \right )}{1000}\right ]](https://tex.z-dn.net/?f=7%5Cleft%20%5Bh_1-h_2%2B%5Cfrac%7BV_1%5E2-V_2%5E2%7D%7B2000g%7D%2Bg%5Cfrac%7B%5Cleft%20%28Z_1-Z_2%20%5Cright%20%29%7D%7B1000%7D%5Cright%20%5D)
+Q
W=![7\left [4+\frac{13^2-23^2}{2000g}+g\frac{\left (40 \right )}{1000}[\right ]](https://tex.z-dn.net/?f=7%5Cleft%20%5B4%2B%5Cfrac%7B13%5E2-23%5E2%7D%7B2000g%7D%2Bg%5Cfrac%7B%5Cleft%20%2840%20%5Cright%20%29%7D%7B1000%7D%5B%5Cright%20%5D)
+
W=44.61KJ
