Identify the true statements about the lumped system analysis.
A. The entire body temperature remains essentially uniform at all times during a heat transfer process.
B. The temperature of lumped system bodies can be taken to be a function of time only.
C. The Biot number is less than or equal to 0.1.
D. The Biot number is greater than or equal to 1.
Suppose we are given three boxes, Box A contains 20 light bulbs, of which 10 are defective, Box B contains 15 light bulbs, of which 7 are defective and Box C contains 10 light bulbs, of which 5 are defective. We select a box at random and then draw a light bulb from that box at random. (a) What is the probability that the bulb is defective? (b) What is the probability that the bulb is good?
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
FOR BRAINLIST HELP PLEASE IS A DCP
A- Causes of the 13t Amendment
B- Reasons for Women's Suffrage
C- Reasons for the Freedmen's Bureau
D- Causes of the Plantation System
Answer:
C
Explanation: Freedmens Bureau provided resources for southerners and newly freed slaves
What 2 things can you never eat for breakfast?
i know the answer but lets see if you do
Answer:
you can't eat your school computer or a pencil.
According to the article, what is one reason why commercial carmakers aim to develop driverless technology?
Incomplete question. However, I inferred you referring to the online article "How automakers can survive the self-driving era."
Explanation:
According to the article, as a result of the perceived demand for autonomous cars in the next few years, this has led to a heightened desire among commercial carmakers to develop driverless technology.
For example, carmakers such as Audi, Toyota have stated projections about the commercial availability of driverless cars.
Air expands through a turbine from 10 bar, 900 K to 1 bar, 500 K. The inlet velocity is small compared to the exit velocity of 100 m/s. The turbine operates at steady state and develops a power output of 3200 kW. Heat transfer between the turbine and its surroundings and potential energy effects are negligible. Calculate the mass flow rate of air, in kg/s, and the exit area, in m2 .
Answer:
- the mass flow rate of air is 7.53 kg/s
- the exit area is 0.108 m²
Explanation:
Given the data in the question;
lets take a look at the steady state energy equation;
m" = W"[tex]_{cv[/tex] / [ (h₁ - h₂ ) -[tex]\frac{V_2^2}{2}[/tex] ]
Now at;
T₁ = 900K, h₁ = 932.93 k³/kg
T₂ = 500 K, h₂ = 503.02 k³/kg
so we substitute, in our given values
m" = [ 3200 kW × [tex]\frac{1\frac{k^3}{s} }{1kW}[/tex] ] / [ (932.93 - 503.02 )k³/kg -[tex]\frac{100^2\frac{m^2}{s^2} }{2}[/tex]|[tex]\frac{ln}{kg\frac{m}{s^2} }[/tex]||[tex]\frac{1kJ}{10^3N-m}[/tex]| ]
m" = 7.53 kg/s
Therefore, the mass flow rate of air is 7.53 kg/s
now, Exit area A₂ = v₂m" / V₂
we know that; pv = RT
so
A₂ = RT₂m" / P₂V₂
so we substitute
A₂ = {[ [tex](\frac{8.314}{28.97}\frac{k^3}{kg.K})[/tex]×[tex]500 K[/tex]×[tex](7.54 kg/s)[/tex] ] / [(1 bar)(100 m/s )]} |[tex]\frac{1 bar}{10N/m^2}[/tex]||[tex]10^3N.m/1k^3[/tex]
A₂ = 0.108 m²
Therefore, the exit area is 0.108 m²
FOR BRAINLIST ITS A DCP
The Battle of Sabine Pass
The Battle of Galveston
The Battle of Palmito Ranch
The Battle of Vicksburg
Answer:
I think The Battle of Sabine Pass
What does it mean to say that PEER is a data-driven, consumer-centric, and comprehensive system?
Answer:
PEER establishes clear performance metrics, it serves consumer needs, and it covers all aspects of energy system performance.
Explanation:
on edg. just did it
Distinguish between systems analysis and systems design?
Answer:
System analysis can be defined as a deep analysis of a part of the structure of a module that has been designed before. System design means to make any module or a part of the structure from scratch and build it completely without estimation.
Explanation:
A low-altitude meteorological research balloon, temperature sensor, and radio transmitter together weigh 2.5 lb. When inflated with helium, the balloon is spherical with a diameter of 4 ft. The volume of the transmitter can be neglected when compared to the balloon's size. The balloon is released from ground level and quickly reaches its terminal ascent velocity. Neglecting variations in the atmosphere's density, how long does it take the balloon to reach an altitude of 1000 ft?
Answer:
12 mins
Explanation:
The summation of the forces in vertical direction
= Fb - Fd - w = 0 ∴ Fd = Fb - w ----- ( 1 )
Fb ( buoyant force ) = Pair * g * Vballoon ------- ( 2 )
Pair = air density , Vballoon = volume of balloon
Vballoon = [tex]\frac{\pi D^3}{6}[/tex] , where D = 4 ∴ Vballoon = 33.51 ft^3
g = 32.2 ft/s^2
From property tables
Pair = 2.33 * 10^-3 slug/ft^3
μ ( dynamic viscosity ) = 3.8 * 10^-7 slug/ft.s
Insert values into equation 2
Fb = ( 2.33 * 10^-3 ) * ( 32.2 ) *( 33.51 ) = 2.514 Ib
∴ Fd = 2.514 - 2.5 = 0.014 Ib ( equation 1 )
Assuming that flow is Laminar and RE < 1
Re = (Pair * vd) / μair -------- ( 3 )
where: Pair = 2.33 * 10^-3 slug/ft^3 , vd = ( 987 * 4 ) ft^2/s , μair = 3.8 * 10^-7 slug/ft.s
Insert values into equation 3
Re = 2.4 * 10^7 ( this means that the assumption above is wrong )
Hence we will use drag force law
Assume Cd = 0.5
Express Fd using the relation below
Fd = 1/2* Cd * Pair * AV^2
therefore V = 1.39 ft/s
Recalculate Reynold's number using v = 1.39 ft/s
Re = 34091
from the figure Cd ≈ 0.5 at Re = 34091
Finally calculate the rise time ( time taken to reach an altitude of 1000 ft )
t = h/v
= 1000 / 1.39 = 719 seconds ≈ 12 mins
What forced induction device is more efficient?
A. Turbo Charger
B. Supercharger
C. Centrifugal Supercharger
D. Procharger
Answer:
A
Explanation:
Answer:
a
Explanation:
Question:
Why is my step-sis stuck in the washing machine every day?
———————————————————————————————-
Please, answer quick! I really need help figuring this out.
Water vapor at 5 bar, 3208C enters a turbine operating at steady state with a volumetric flow rate of 0.65 m3/s and expands adiabatically to an exit state of 1 bar, 1608C. Kinetic and potential energy effects are negligible. Determine for the turbine (a) the power developed, in kW, (b) the rate of entropy production, in kW/K, and (c) the isentropic turbine efficiency.
Answer:
A) 371.28 kW
b) 0.1547 Kw/K
c) 85%
Explanation:
pressure (p1) = 5 bar
exit pressure ( p2 ) = 1 bar
Initial Temperature ( T1 ) = 320°C
Final temp ( T2 ) = 160°C
Volume ( V ) = 0.65 m^3/s
A) Calculate power developed ( kW )
P = m( h1 - h2 ) = 1.2 ( 3105.6 - 2796.2 ) = 371.28 kW
B) Calculate the rate of entropy production
Δs = m ( S2 - S1 ) = 1.2 ( 7.6597 - 7.5308 ) = 0.1547 Kw/K
c) Calculate the isentropic turbine efficiency
For an isentropic condition : S2s = S1
therefore at state , value of h2 at isentropic condition
attached below is the remaining part of the solution
Note : values of [ h1, h2, s1, s2 , v1 and m ] are gotten from the steam tables at state 1 and state 2
You would use a _____________ gauge to check the pressure in each tire. A technician should compare the tire-pressure reading with the tire pressure specified on the side of the driver's _____________ . When servicing tires follow the _____________ procedure outlined in the owner’s manual or online service information. Correct tire-inflation pressure is printed on a placard on the _____________. Why are tires rotated? Which tire rotation method is most often recommended? _____________ An easy way to remember effective tire rotation is, “Drive wheels straight, _____________ the nondrive wheels.” A _____________ is used to ensure that the proper torque is completed on a
Answer:
the first one is tire pressure gauge :)
Explanation:
Silicon diodes are used in bridge rectifier circuit to supply a load (1002) with 24 volts DC, computerms voltage and current, the ripple factor, and the efficiency of the rectifier.
Answer:
a) 26.66 volts , 266.2 mA
b) 0.458
c) 81%
Explanation:
load ( R ) = 100 Ω
voltage source = 24 volts DC
a) Calculate the rms voltage and current
Vrms = Vp / √ 2
where : Vp = (voltage source * [tex]\pi[/tex]) / 2 = ( 24 *
∴ Vrms = 12[tex]\pi[/tex] / √2 = 26.66 volts
Irms = Vrms / R = 26.66 / 100 = 0.2666 = 266.6 mA
b) Calculate the Ripple factor
Ripple factor for a bridge rectifier = √( 1.1^2 - 1 ) = 0.458
c) Calculate the efficiency of the rectifier
efficiency = ( output dc power ) / Input ac power
= ( 24 / 100 )^2 * 100) / ( 26.66 * 0.2666 )
= 0.0576 * 100 / 7.11 = 0.81 = 81%
Alicia had to get over her fear of heights in order to become comfortable maintaining the generators in wind turbines. professional certification exam verifies the knowledge of the testee, whereas the CMP verifies green activity of the certified professional. A professional certification exam verifies the current qualifications of the testee, whereas the CMP ensures the certified professional continues to exhibit those qualifications. A professional certification exam verifies the qualifications of the testee, whereas the CMP measures the actual green commitment of the certified professional. A professional certification exam verifies the current knowledge of the testee, whereas the CMP ensures the certified professional continues to add to that knowledge.
Answer:a
Explanation:
A 0.06-m3 rigid tank initially contains refrigerant- 134a at 0.8 MPa and 100 percent quality. The tank is connected by a valve to a supply line that carries refrigerant- 134a at 1.2 MPa and 36°C. Now the valve is opened, and the refrigerant is allowed to enter the tank. The valve is closed when it is observed that the tank contains saturated liquid at 1.2 MPa. Determine (a) the mass of the refrigerant that has
entered the tank and (b) the amount of heat transfer.
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
kam
How much time in education is needed
if you desire to eventually run a
research laboratory in science?
A. 2 years
B. 4 years
C. 7 years
D. 10 years
Factors such as brake shoe orientation, pin location, and direction of rotation determine whether a particular brake shoe is considered to be self-energizing or self-deenergizing. Sketch a brake drum where the left shoe is self-energizing and the right shoe is self-deenergizing. Which shoe will produce more braking torque, assuming equal actuation forces and identical brake shoes
Answer:
Self energizing brake shoe produces more Torque
Explanation:
Attached below is the sketches of the various cases
The cases are :
case 1 ; deenergizing
case 2 ; self energizing
case 3 ; produces high braking torque
For a brake to be self energizing when the Frictional torque and braking torque are in the same direction
summary from equation 3
when: b > uc the brake is controllable
b = uc It is self locking
b < uc The brake is uncontrollable
Test if a number grade is an A (greater than or equal to 90). If so, print "Great!". Hint: Grades may be decimals. Sample Run Enter a Number: 98.5 Sample Output Great!
Answer:
In Python:
grade = float(input("Enter a Number: "))
if grade >= 90:
print("Great!")
Explanation:
This prompts the user for grade
grade = float(input("Enter a Number: "))
This checks for input greater than or equal to 90
if grade >= 90:
If yes, this prints "Great"
print("Great!")
When you park on a hill,the direction your __are pointed determines which direction your car will roll if the breaks fail
Answer:
Tires or wheels? I think this is the answer. ^_^
Explanation:
Which option distinguishes the type of software the team should use in the following scenario?
A development team needs to create a code of detailed instructions for producing automobile dashboards for a large United States automaker.
a. computer-aided engineering software
b. digital manufacturing software
c. geographic mapping software
d. computer-aided manufacturing software
AA
Tools
Submit Test
info
1
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Careers in Agricultural Science: Mastery Test
1
Select the correct answer.
A certain noodle brand was taken off supermarket shelves because it did not conform to standards set by US regulatory agencies. The internal
team investigating the matter concluded that Luke Brown failed in his duty. What do you think was Luke's position in the company?
OA.
food production supervisor
OB
food safety and quality assurance manager
C.
research and development technician
OD
food and drug inspector
Reset
Next
Answer:
B. food safety and quality assurance manager
Explanation:
PLATO
What can be used to measure the alcohol content in gasoline? A. Graduated cylinder B. Electronic tester C. Scan tool D. Either a graduated cylinder or an electronic tester
Answer:
GRADUATED CYLINDER
Explanation:
Nitrogen (N2) enters an insulated compressor operating at steady state at 1 bar, 378C with a mass flow rate of 1000 kg/h and exits at 10 bar. Kinetic and potential energy effects are negligible. The nitrogen can be modeled as an ideal gas with k 5 1.391. (a) Determine the minimum theoretical power input required, in kW, and the corresponding exit temperature, in 8C. (b) If the exit temperature is 3978C, determine the power input, in kW, and the isentropic compressor efficiency.
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%
A hydraulic cylinder pushes a heavy tool during the outward stroke, placing a compressive load of 400Ib in the piston rod. During the return stroke, the rod pulls on the tool with a force of 1500Ib. Calculate the resulting design factor for the 0.6 in-diameter rod when subjected to this pattern of forces for many cycles. Discuss your result and justify if the design factor is appropriate, too low or too high. The material is SAE 4130 WQT 1300 steel. Assume wrought steel, machined, and 99% reliability.
A stream of refrigerant-134a at 100 psia and 30°F is mixed with another stream at 100 psia and 80°F. If the mass flow rate of the cold stream is twice that of the hot one and the pressure is not changed, determine the enthalpy of the exit stream in Btu/lbm (with three significant figures).
Answer:
The specific enthalpy of the exit stream is 63.267 Btu per pound-mass.
Explanation:
This case represents a mixing chamber, a steady state device where two streams of the same fluid (cold and hot streams) are mixed with negigible changes in kinetic and gravitational potential energy and likewise in heat work interactions with surroundings. By Principle of Mass Conservation and First Law of Thermodynamics we have the following Mass and Energy Balances:
Mass Balance
[tex]3\cdot \dot m_{in} - \dot m_{out} = 0[/tex] (1)
Where:
[tex]\dot m_{in}[/tex] - Mass flow of the hot stream, in pounds-mass per second.
[tex]\dot m_{out}[/tex] - Mass flow of the resulting stream, in pounds-mass per second.
Energy Balance
[tex]2\cdot \dot m_{in}\cdot h_{c}+\dot m_{in}\cdot h_{H}-\dot m_{out}\cdot h_{out} = 0[/tex] (2)
Where:
[tex]h_{c}[/tex] - Specific enthalpy of the cold stream, in BTU per pound-mass.
[tex]h_{h}[/tex] - Specific enthalpy of the hot stream, in BTU per pound-mass.
[tex]h_{out}[/tex] - Specific enthalpy of the resulting stream, in BTU per pound-mass.
By applying (1) in (2) we eliminate [tex]\dot m_{in}[/tex] and clear [tex]h_{h}[/tex]:
[tex]h_{out} = \frac{2\cdot h_{c}+h_{h}}{3}[/tex]
From Property Charts of the Refrigerant 134a, we have the following information:
Cold fluid (Subcooled liquid)
[tex]p = 100\,psia[/tex]
[tex]T = 30\,^{\circ}F[/tex]
[tex]h_{c} \approx 37.870\,\frac{Btu}{lbm}[/tex]
Hot fluid (Superheated steam)
[tex]p = 100\,psia[/tex]
[tex]T = 80\,^{\circ}F[/tex]
[tex]h_{h} = 114.06\,\frac{Btu}{lbm}[/tex]
If we know that [tex]h_{c} \approx 37.870\,\frac{Btu}{lbm}[/tex] and [tex]h_{h} = 114.06\,\frac{Btu}{lbm}[/tex], then the specific enthalpy of the resulting stream is:
[tex]h_{out} = 63.267\,\frac{Btu}{lbm}[/tex]
The specific enthalpy of the exit stream is 63.267 Btu per pound-mass.
An oil with density 900 kg/m3 and kinematic viscosity 0.0002 m2/s flows upward through an inclined pipe as shown in figure below. The pressure and elevation are known at sections 1 and 2, 10 m apart. Assuming steady laminar flow
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.
What is density?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
#SPJ2
Can someone tell me what car, year, and model this is please
Answer:
Explanation:
2019 nissan altima 2.5 SV
have a good day /night
may i please have a branlliest
The Aluminum Electrical Conductor Handbook lists a dc resistance of 0.01558 ohm per 1000 ft at 208C and a 60-Hz resistance of 0.0956 ohm per mile at 508C for the all-aluminum Marigold conductor, which has 61 strands and whose size is 1113 kcmil. Assuming an increase in resistance of 2% for spiraling, calculate and verify the dc resistance. Then calculate the dc resistance at 508C, and determine the percentage increase due to skin effect.
Answer:
a) 0.01558 Ω per 1000 feet
b) 0.0923 Ω per mile
c) 3.57%
Explanation:
a) Calculate and verify the DC resistance
Dc resistance = R = р [tex]\frac{l}{A}[/tex]
for aluminum at 20°C
р = 17 Ωcmil/ft
hence R = 17 * 1000 / ( 113000 ) = 0.01527 Ω per 1000 feet
there when there is an increase in resistance of 2% spiraling
R = 1.02 * 0.01527 = 0.01558 Ω per 1000 feet
b) Calculate the DC resistance at 50°C
R2 = R1 ( [tex]\frac{T+t2}{T+ t1}[/tex] )
where ; R1 = 0.01558 , T = 228 , t2 = 50, t1 = 20 ( input values into equation above )
hence R2 = ( 0.01746 / 0.189 ) Ω per mile = 0.0923 Ω per mile
c ) Determine the percentage increase due to skin effect
AC resistance = 0.0956 ohm per mile
Hence; Increase in skin effect
= ( 0.0956 -0.0923 ) / 0.0923
= 0.0357 ≈ 3.57%