2. In a certain Village in eastern Uganda, residents use on average 1.5 Kg per inhabitant of
wood per day in a traditional stove of 12% efficiency. If the village has 200 in habitants,
Find,
i.
The
total mass of wood consumed daily.
ii.
The Energy demand of the village in KWh.
iii.
The actual energy consumption of the village in KWh.
iv.
If an investor would like to provide this village with a new energy converter of 30%
efficiency, how many Kilograms of wood will be required per day

Answer:

A)

i) 592.2 k

ii) - 80 kw

B)

i) 105.86 kw

ii) 78%

Explanation:

Note : Nitrogen is modelled as an ideal gas hence R - value = 0.287

A) Determine the minimum theoretical power input required  and exit temp

i) Exit temperature :

[tex]\frac{T_{2s} }{T_{1} } = (\frac{P2}{P1} )^{\frac{k-1}{k} }[/tex]

∴ [tex]T_{2s}[/tex]  = ( 37 + 273 ) * [tex](\frac{10}{1} )^{\frac{1.391-1}{1.391} }[/tex]  =  592.2 k

ii) Theoretical power input :

W = [tex]\frac{-n}{n-1} mR(T_{2} - T_{1} )[/tex]

where : n = 1.391 , m = 1000/3600 , T2= 592.2 , T1 = 310 , R = 0.287

W = - 80 kW  ( i.e. power supplied to the system )

B) Determine power input and Isentropic compressor efficiency

Given Temperature = 3978C

i) power input to compressor

W = m* [tex]\frac{1}{M}[/tex] ( h2 - h1 )

h2 = 19685 kJ/ kmol ( value gotten from Nitrogen table at temp = 670k )

h1 = 9014 kj/kmol ( value gotten from Nitrogen table at temp = 310 k )

m = 1000/3600 ,  M = 28

input values into equation above

W = 105.86 kw

ii) compressor efficiency

П = ideal work output / actual work output

   = ( h2s - h1 ) / ( h2 - h1 ) = ( T2s - T1 ) / ( T2 - T1 )

  = ( 592.2 - 310 ) / ( 670 - 310 )

  = 0.784 ≈ 78%

Answer: A. whether his geology studies exposed him to principles of geotechnical engineering

Explanation:

The options include:

a. whether his geology studies exposed him to principles of geotechnical engineering

b. the size of the geology program he attended

c. the size of the architecture firm

d. whether the architecture firm was intending to offer Miguel a full-time position

Since Miguel, is a former geology student with experience as an intern at an architecture firm, and Sarah is considering him for an assistant site investigation position, the option that will be relevant for her to make a decision is to know whether his geology studies exposed him to principles of geotechnical engineering.

Geotechnical engineering, is a branch of engineering that makes use of principles of rock mechanics to solve engineering challenges. Since Sarah needs him for an assistant site investigation position, he'll need to investigate souls, rocks and evaluate them.

Answer:

a) 0.50613

b) 22.639 kJ

Explanation:

From table A-11 , we will make use of the properties of Refrigerant R-13a at 24°C

first step : calculate the  volume of R-13a  ( values gotten from table A-11 )

V = m1 * v1 = 5 * 0.0008261 = 0.00413 m^3

next : calculate final specific volume ( v2 )

v2 = V / m2 = 0.00413 / 0.25 ≈ 0.01652 m^3/kg

a) Calculate the mass of refrigerant that entered the tank

v2 = Vf + x2 * Vfg

v2 = Vf +  [ x2 * ( Vg - Vf ) ] ----- ( 1 )

where:  Vf = 0.0008261 m^3/kg, V2 = 0.01652 m^3/kg , Vg = 0.031834 m^3/kg  ( insert values into equation 1 above )

x2 = ( 0.01652 - 0.0008261 ) / 0.031834

     = 0.50613 ( mass of refrigerant that entered tank )

b) Calculate the amount of heat transfer

Final specific internal energy = u2 = Uf + ( x2 + Ufg ) ----- ( 2 )

uf = 84.44 kj/kg , x2 = 0.50613 , Ufg = 158.65 Kj/kg

therefore U2 = 164.737 Kj/kg

The mass balance  ( me ) = m1 - m2 --- ( 3 )

energy balance( Qin ) = ( m2 * u2 ) - ( m1 * u1 ) + ( m1 - m2 ) * he

therefore Qin = 41.184 - 422.2 + 403.655  = 22.639 kJ

Answer:

0.49

0.51

Explanation:

Probability that bulb is defective :

Let :

b1 = box 1 ; b2 = box 2 ; b3 = box 3

d = defective

P(defective bulb) = (p(b1) * (d|b1)) + (p(b2) * p(d|b2)) + (p(b3) * p(d|b3))

P(defective bulb) = (1/3 * 10/20) + (1/3 * 7/15) + (1/3 * 5/10))

P(defective bulb) = 10/60 + 7/45 + 5/30

P(defective bulb) = 1/6 + 7/45 + 1/6 = 0.4888

= 0.49

P(bulb is good) = 1 - P(defective bulb) = 1 - 0.49 = 0.51

Answer:

C

Explanation: Freedmens Bureau provided resources for southerners and newly freed slaves

Answer:

P=900KG/M3

U=0.0002 M2/S

RE=PV/U

=900*10/0.0002

=45000000

Explanation:

The Reynold number will be 4.5×10⁷. Reynold's number is found as the ratio of the inertial to the viscous force.

Density is defined as the mass per unit volume. It is an important parameter in order to understand the fluid and its properties. Its unit is kg/m³.

The mass and density relation is given as

mass = density × volume

The ratio of inertial to viscous force is known as Reynold's number.

[tex]\rm R_E= \frac{\rho u L}{\mu} \\\\ \rm R_E=\frac{900 \times 10}{0.0002} \\\\ R_E=45000000[/tex]

Hence, the Reynold number will be 4.5×10⁷.

To learn more about the density refers to the link;

brainly.com/question/952755

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