Answer:
275 Kelvin
Explanation:
Coefficient of Performance=11
[tex]T_H=\text {Absolute Temperature of high temperature reservoir=300 K}[/tex]
[tex]T_L=\text {Absolute Temperature of low temperature reservoir}[/tex]
[tex]\text {Coefficient of performance for carnot cooler}\\=\frac {T_L}{T_H-T_L}\\\Rightarrow 11=\frac{T_L}{300-T_L}\\\Rightarrow 11(300-T_L)=T_L\\\Rightarrow 3300-11T_L=T_L\\\Rightarrow 3300=T_L+11T_L\\\Rightarrow 3300=12T_L\\\Rightarrow T_L=\frac {3300}{12}\\\Rightarrow T_L=275\ K\\\Therefore \text{Temperature at which the refrigerator absorbs heat=275 Kelvin}[/tex]
The difference between absolute viscosity and kinematic viscosity is a. the absolute viscosity is the mass density divided by the kinematic viscosity c. absolute viscosity relates absolute pressure, film thickness and velocity while kinematic viscosity b. the kinematic viscosity is the absolute viscosity divided by the mass density relates shear stress and relative pressure e. all of the above
Answer:
b).the kinematic viscosity is absolute viscosity divided by mass density
Explanation:
Viscosity is a fluid property that offers resistance or obstruction to deformation or fluid flow.
Viscosity is of two types--
1. Absolute viscosity , μ
2. Kinematic viscosity, ν
Absolute viscosity :
Absolute viscosity is also called the dynamic viscosity. It is the internal resistance of the fluid to flow.
Kinematic viscosity :
Kinematic viscosity is the ratio of dynamic viscosity to the density of the fluid.
Absolute viscosity measures a fluid's internal friction, while kinematic viscosity is the ratio of absolute viscosity to the fluid's density. Viscosity affects how easily a liquid flows; higher intermolecular forces lead to higher viscosity, and this property is critical in fluid dynamics studies.
Explanation:The difference between absolute viscosity and kinematic viscosity is that absolute viscosity, often referred to simply as viscosity, represents the fluid's resistance to flow and is a measure of the internal friction within the fluid. Kinematic viscosity, on the other hand, takes the fluid's density into account and is the ratio of the fluid's absolute viscosity to its density. While absolute viscosity is measured in units like Pascal-seconds (Pa·s), kinematic viscosity is measured in square meters per second (m²/s).
Viscosity is influenced by intermolecular forces; liquids that can flow easily, such as ethanol, have lower viscosities, while substances like motor oil with higher intermolecular forces have higher viscosities. Measuring the time it takes for steel balls to fall through a fluid or for a fluid to flow through a narrow tube helps determine the fluid's viscosity. In other words, absolute viscosity is concerned with the sheer strength and flow resistance of a fluid, while kinematic viscosity relates to the movement of the fluid under the force of gravity considering its volume.
A gas contained within a piston-cylinder undergoes the follow change in states: Process 1: Constant volume from p1 = 1 bar V1 = 2.6 m3 to state 2 with p2 = 2.7 bar Process 2: Compression to V3 = 1.5 m3, which the pressure-volume relationship is pV = constant. Process 3: Constant pressure to state 4, where V4 = 0.5 m3. Sketch the processes on p-V graph and evaluate the work for each process in kJ.
Answer:
Process 1:W=0
Process 2:W= -386.13 KJ
Process 3:W= -468 KJ
Explanation:
Process 1:[tex]P_1=1 bar,V_1=2.6m^3[/tex]
Process 2:[tex]P_2=2.7bar,V_2=2.6m^3[/tex]
Process 3:[tex]V_3=1.5 m^3[/tex]
[tex]V_4=0.5 m^3[/tex]
Process 1:
Work (W)=0 ,because it is constant volume process.
Process 2:
It is constant temperature process so PV=C
[tex]P_2V_2=P_3V_3[/tex]
[tex]P_3=\dfrac{P_2V_2}{V_3}[/tex]
[tex]P_3=\dfrac{2.7\times 2.6}{1.5}[/tex]
[tex]P_3=4.68 [/tex]bar
So work in constant temperature process
W=[tex]P_2V_2\ ln\dfrac{V_3}{V_2}[/tex]
W=[tex]270\times 2.6\ ln\dfrac{1.5}{2.6}[/tex] (1 bar=100KPa)
W= -386.13 KJ
Negative sign means it is compression process.
Process 3:
It is a constant pressure.
So work W=[tex]P_3(V_4-V_3)[/tex]
W=468(0.5-1.5) KJ
W= -468 KJ
Negative sign means it is compression process.
In a quasi-static process, the system remains infinitesimally close to equilibrium throughout the process. a)True b) False
Answer:
It is True that in a quasi static process, the system remains infinitesimally close to equilibrium state throughout the process.
Explanation:
The literal meaning of the word "quasi" is 'almost' and static is 'rest', so quasi static state means almost at rest state of the system
It can be further explained as the process, in thermodynamics which allows the system to be carried to slowly to maintain its equilibrium or to remain in its internal equilibrium state. Such a process is known as quasi-static process. Such processes also allow all isothermal and adiabatic processes to operate slowly so as not to disturb their internal equilibrium. this makes the system to always remain in thermal equilibrium
A pendulum has an oscillation frequency (T) which is assumed to depend upon its length (L), load mass (m) and the acceleration of gravity (g). Determine the relationship between oscillation frequency, length, load mass and acceleration of gravity. Differentiate as well which variable does not affect the oscillation frequency.
Answer:
Mass does not affect oscillation frequency.
Explanation:
Let the bob of the pendulum makes a small angular displacement θ. When the pendulum is displaced from the equilibrium position, a restoring force tries to act upon it and it tries to bring the pendulum back to its equilibrium position. Let this restoring force be F.
Therefore, F = -mgsinθ
Now for pendulum, for small angle of θ,
sinθ[tex]\simeq[/tex]θ
Therefore, F = -mgθ
Now from Newton's 2nd law of motion,
F = m.a = -mgθ
[tex]\Rightarrow m.\frac{d^{2}x}{dt^{2}} = - mg\Theta[/tex]
Now since, x = θ.L
[tex]\Rightarrow L.\frac{d^{2}\Theta }{dt^{2}}= -g\Theta[/tex]
[tex]\Rightarrow \frac{d^{2}\Theta }{dt^{2}}= -\frac{g}{L}.\Theta[/tex]
[tex]\Rightarrow \frac{d^{2}\Theta }{dt^{2}}+\frac{g}{L}.\Theta =0[/tex]
Therefore, angular frequency
[tex]\omega ^{2}[/tex] = [tex]\frac{g}{L}[/tex]
ω = [tex]\sqrt{\frac{g}{L}}[/tex]
Also we know angular frequency is , ω = 2.π.f
where f is frequency
Therefore
2πf = [tex]\sqrt{\frac{g}{L}}[/tex]
f = [tex]\frac{1}{2 \pi }\sqrt{\frac{g}{L}}[/tex]
So from here we can see that frequency,f is independent of mass, hence it does not affect frequency.
In a nuclear reactor, more fuel is burned than is consumed. a)-True b)- False
Answer:
true
Explanation:
yes, it is true more fuel is burned than is consumed.
nuclear reactor generate electricity from nuclear fission and while nuclear fission nucleus splits into small parts to generate energy.
these energies can be used for my purposes mainly it is used for power generation.
we can also say that in nuclear reactor more fuel is consumed because of metal acting as a fissionable material.
An electric motor is to be supported by four identical mounts. Each mount can be treated as a linear prevent problems due required that the amplitude of motion should not exceed 0.1 mm per 1 N of unbalance force. The mass of the motor is 120 kg and the operating speed is 720 rpm Use the concept of transfer function to determine the required stiffhess coefficient of each mount.
GIVEN:
Amplitude, A = 0.1mm
Force, F =1 N
mass of motor, m = 120 kg
operating speed, N = 720 rpm
[tex]\frac{A}{F}[/tex] = [tex]\frac{0.1\times 10^{-3}}{1} = 0.1\times 10^{-3}[/tex]
Formula Used:
[tex]A = \frac{F}{\sqrt{(K_{t} - m\omega ^{2}) +(\zeta \omega ^{2})}}[/tex]
Solution:
Let Stiffness be denoted by 'K' for each mounting, then for 4 mountings it is 4K
We know that:
[tex]\omega = \frac{2 \pi\times N}{60}[/tex]
so,
[tex]\omega = \frac{2 \pi\times 720}{60}[/tex] = 75.39 rad/s
Using the given formula:
Damping is negligible, so, [tex]\zeta = 0[/tex]
[tex]\frac{A}{F}[/tex] will give the tranfer function
Therefore,
[tex]\frac{A}{F}[/tex] = [tex] \frac{1}{\sqrt{(4K - 120\ ^{2})}}[/tex]
[tex]0.1\times 10^{-3}[/tex] = [tex] \frac{1}{\sqrt{(4K - 120\ ^{2})}}[/tex]
Required stiffness coefficient, K = 173009 N/m = 173.01 N/mm
What are beats? Determine the terms decibel and octave.
Answer:
Explained below
Explanation:
Beats are interference pattern between two sounds of slightly different frequencies perceived as periodic vibration in volume whose rate is difference of the two.
Both octave and decibel are the terms of measurement.
Octave(In electronics) is a logarithmic unit for ratio between frequencies,with one octave corresponding to doubling of frequency. For example frequency one octave is from 40 Hz to 80 Hz.
Whereas decibel is a unit of sound intensity. It is one-tenth of A bel. In electronics it is used measure power level of an electrical signal by comparing it with given level of logarithmic scale.
Define spring stiffness and damping constant.
Answer Explanation:
SPRING STIFFNESS :The stiffness of a body is a measure of resistance offered by an elastic body to deformation.it is denoted by K every object has some stiffness for spring the spring stiffness is the force required to cause unit deflection
DAMPING CONSTANT: the damping constant is a number decided by manufacturer that describes the material property. Damping is an influence within an oscillatory system that has the effect of restricting its oscillation
A(n)_____ is a device that provides the power and motion to manipulate the moving parts of a valve or damper used to control fluid flow. A. actuator B. pilot-operated regulator C. ratio regulator D. sliding stem
Answer:
Out of the four options provided
option A. actuator
is correct
Explanation:
An actuator is the only device out of the four mentioned devices that provides power and ensures the motion in it in order to manipulate the movement of the moving parts of the damper or a valve used whereas others like ratio regulator are used to regulate air or gas ratio and none mof the 3 remaining options serves the purpose
Harvesting wind energy using kites is: a) possible but currently very expensive. b) possible and currently inexpensive compared to wind turbines c) possible using a single kite.
Answer: b) possible and currently inexpensive as compared to wind turbines.
Explanation: Wind harvesting through kites is a process that will require less expenses in making and maintenance of it .Kites can be termed as the wind generator that is unconventional. The set up for the kite wind generator is also easy to install and also less costly as compared with turbines. So the correct option is option(a) .
Intrinsic semiconduction is a property of a pure material. (True , False )
True.
An intrinsic semiconductor is a pure semiconductor. At room temperature it behaves as an insulator because it only has a few free and hollow electrons due to thermal energy.
In an intrinsic semiconductor there are also electron fluxes and gaps, although the total current resulting is zero. This is because the action of thermal energy produces free electrons and gaps in pairs, so there are as many free electrons as there are gaps with which the total current is zero.
If a host system is 80% efficient, the minimum horsepower rating of the motor should be ? if the hoist is to provide 20,000 ft-lb/s. a) 45.45hp b) 23,530hp c) 36.36hp d) 42.78hp
Answer:
answer is option A i.e.45.45 hp
Explanation:
Given data:
load =20000 ft lb/s
efficiency = 80%
we know that
1 hp = 550 ft lb/s
minimum horsepower rating can be obtained by using following formula
minimum horse power rating = [tex]\frac{load}{efficiency * 1 horse power} \\[/tex]
= [tex]\frac{20000}{0.8*550} = 45.45 hp[/tex]
Vertical axis wind turbine generates more electrical power compared to horizontal axis wind turbine due to differences in wind speed. a)-True b)- False
Answer: False
Explanation: Horizontal-axis wind turbine is the major part of wind industry. Horizontal axis have rotating axis of wind turbine in horizontal direction.Horizontal wind produces more electricity from a particular amount of wind that is provided and thus is preferred more.
vertical-axis wind turbines have the rotational axis of the turbine in vertical or perpendicular direction and have easy installation even where wind conditions are not predictable and is lighter in weight but are not able to produce the large amount of electricity as compared to horizontal-axis wind turbine.
Thus the statement given is false.
A horizontal jet of water strikes a vertical surface on a stationary cart that has a mass of 2.8 kg. The jet has a mass flow rate of 0.13 kg/s. The force required to hold the cart in place is 8N. What is the diameter of the nozzle? a. 1.6 mm b. 5.1 mm c. 3.4 mm d. 7.3 mm
Answer:
option a is correct answer i.e. d = 1.6 mm
Explanation:
From conservation principle
force by jet = force required to hold the jet
force by the jet is written as
[tex]force = \dot{m}(v_{1}-v_{2})\[/tex]
force required to hold the jet = 8N
[tex]\dot{m}(v_{1})\ = 8[/tex]
[tex]\dot{m}=0.13 kg/s[/tex]
[tex]v_{1} = 61.58 m/s[/tex]
we know that mass flow rate is given as
[tex]\dot{m}=\rho Av_{1}[/tex]
substituting value to get required diameter of the nozzle
[tex]0.13=1000*\frac{\pi }{4}d^{2}*61.58[/tex]
d = 1.6 mm
What is a substitutional solid solution? And what factors favor the formation of a substitu- tional solid solution?
Answer:
A substitutional solid solution is a kind of alloying process used to improve or strengthen a purer metal by alloying it. this process works out by adding atoms of an alloy element to the atoms of the crystal lattice of the parent or base element, thus forming a substitutional solid solution. This process generates local non uniformity in the lattice due to the presence or mixing of an alloy element with the base element which impedes the plastic deformation.
Factors that favor the formation of substitutional solid solution are:
Alloying beyond the solubility limitChemical affinity of the elementsRelative atomic size of the particlesCrystal structure of the elementsValenceAnswer:
Substitutional solids solution are formed when there is change in position of atom named as A in lattice by some other atoms of different atoms named as B.
Explanation:
Substitutional solids solution are formed when there is change in position of atom named as A in lattice by some other atoms of different atoms named as B.
Strengthening of this solution occurs when solute atom is lager than solvent atom so that it can replace its position
factor affect the extent of solid solution is
1) Relative atomic size
2) crystal structure
3) chemical affinity
4) valency
An electric heater draws 12 A from a 120 V power source. How much powe heater dissipate? (a) 10 W (b) 1200 W (c) 1440 W (d) 17,280 W
Answer:
c) 1440 W
Explanation:
P = V*i = (12A)*(120V) = 1440W
According to the scenario, the amount of power that is dissipated by the heater is 1440 W. Thus, the correct option for this question is C.
What is Power?Power may be defined as the amount of energy that is significantly transferred or converted per unit of time. The unit of power is the watt (W). It may be typically calculated with the help of the given formula:
P = W/Δt.According to the context of this question, the amount of power that is dissipated within the heater is calculated by the following formula:
P = V × i = 12 × 120 = 1440 W.Therefore, according to the scenario, the amount of power that is dissipated by the heater is 1440 W. Thus, the correct option for this question is C.
To learn more about Power, refer to the link:
https://brainly.com/question/1634438
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It is not a practical proposition to take direct measurements in nanoscale, but we can estimate variations in position and momentum of particles by a)-Scanning Electron Microscopes b)-Transmission Electron Microscope c)-Heisenberg Uncertainly Principle d)- None of the above
Answer:
Answer is c Heisenberg's uncertainty principle
Explanation:
According to Heisenberg's uncertainty principle there is always an inherent uncertainty in measuring the position and momentum of a particle simultaneously.
Mathematically
[tex]\Delta x\times \Delta \overrightarrow{p}\geq \frac{h}{4\pi }[/tex]
here 'h' is planck's constant
Three point bending is better than tensile for evaluating the strength of ceramics. a)-True b)- False
Answer:
a)-True
Explanation:
Three point bending is better than tensile for evaluating the strength of ceramics. It is got a positive benefit to tensile for evaluating the strength of ceramics.
An unknown gas (k=1.4, c v= 0.716 kJ/kg.K, c_p=1 kJ/kg.K, R = 0287 kJ/kg K) is trapped in a 1 m^3 piston-cylinder device at 1000 KPa and 1000 K. It then undergoes an isothermal (constant-temp) process in which 696 kJ of boundary work is delivered (positive work transfer). Determine the heat transfer. (Use the PG model).
Answer:
So heat transfer is 696 kJ
Explanation:
Given:
K = 1.4
[tex]C_{v}[/tex] = 0.716 kJ/kg
[tex]C_{p}[/tex] = 1 kJ/kg
R = 0.287 kJ/kg
V = 1 [tex]m^{3}[/tex]
P = 1000 kPa
T = 1000 K
Work delivered, δW = 696 kJ
It is isothermal process, so the initial and final temperature are same, that is T₁ = T₂ and the internal energy is zero (dU =0)
Therefore from 1st law of thermodynamcis,
δQ = dU + δW
= 0 + 696
= 696 kJ
So heat transfer is 696 kJ
A stainlesss steel cylinder diameter 60 mm is cooled in a air with h = 10 W/m^2-K. If the thermal conductivity is 20 W/m-K, the Biot number for this sphere is a)-0.005 b)-0.03 c)-8 d)-30
Answer:
The Biot number for this sphere is 0.03
Explanation:
Given data in equation
diameter (d) = 60 mm = 60/1000 = 0.06 m
heat transfer coefficient (h) = 10 w/m²-K
thermal conductivity (K) = 20 W/m-K
To find out
Biot number for sphere
Solution
we will find boit number by this given formula
Biot Number = ( h × S ) / K ..................1
here h and K value is given in question
and S = diameter/2
S= 60/2 = 30 mm = 0.03 m
Now put these value S, h and K in equation 1
Biot Number = ( 10 × 0.03 ) / 10
Biot Number = 0.03
A water pipe with a 5 cm inner diameter is designed for to have a flow rate of 75 Umin. What is the entrance length for this pipe (in cm)?
Answer:
121.20 cm
Explanation:
Given data in question
inner dia = 5 cm
flow rate = 75 umin = 1.25 ×10³ cm³/sec
Solution
First we calculate Re by this formula
Re= [tex]\frac{V × D}{v)}[/tex] = [tex]\frac{Q × D}{π/4 × D²× v)}[/tex]
Re= [tex]\frac{4Q }{π × D× v)}[/tex]
here we know Q is flow rate and D is dia of pipe and v is kinematic viscosity that is 1.14 × [tex]10^{-2}[/tex] cm ² / sec
so Re= [tex]\frac{4Q }{π × D× v)}[/tex]
Re = [tex]\frac{4×1.25× 10³ }{π × 5 × 1.14 × 10^{-2} )}[/tex]
So Re will be 27936 that is greater than 4000 thats why it is turbulent flow
and we know [tex]\frac{Length}{dia)}[/tex] ≡ 4.4 [tex]Re^{1/6}[/tex]
so [tex]\frac{Length}{dia)}[/tex] ≡ 24.24
length will be 121.20 cm
________is defined to be the probability that a failed component or system will be restored to a repaired specified condition within a period of time when maintenance is performed in accordance with prescribed procedures
Answer:
Repairable component
Explanation:
Repairable component is defined to be the probability that a failed component or system will be restored to a repaired specified condition within a period of time when maintenance is performed in accordance with prescribed procedures.
________is defined to be the probability that a failed component or system will be restored to a repaired specified condition within a period of time when maintenance is performed in accordance with prescribed procedures
Repairable component
What is/are the benefit(s) of short fibre reinforcements? A)Increased stiffness only. B)Increased strength and increased Toughness. C) Increased Toughness and increased flexibility. D) None of the above.
Answer: B) Increased strength and increased toughness
Explanation: Short fibre reinforcement has the major property of being tough and has high strength. Short fibre reinforcement is basically a process of addition of the short fibre to the thermoplastic materials to make the improvement in their quality and working by increasing their strength.They also have application in many areas because of their hardness property as well as being cost -effective. Thus, the option (b) is the correct option.
The temperature in a pressure cooker is 130 degree C while the water is boiling. Determine the pressure inside the cooker.
If water is boiling at 130 degrees Celsius inside a pressure cooker, the pressure is approximately 2.7 atmospheres
To determine the pressure inside a pressure cooker where water is boiling at 130 degrees Celsius, we use the properties of water and its boiling point at various pressures.
For water, the pressure at which the boiling point is elevated to 130 degrees Celsius can be found using steam tables.
At 130 degrees Celsius, the saturation pressure of water is approximately 2.7 atmospheres (atm). This is equivalent to :
= 2.7 x 101.325 kPa
= 273.5775 kPa, or about 2.7 bar (since 1 bar = 100 kPa)
Heat conduction is a function of material property, temperature difference and fluid the geometry of the object. a) True b) False
Answer:
a)True
Explanation:
According to Fourier's law,It states that Heat transfer is directly proportionate to the temperature gradient.For unidirectional conduction
[tex]q''\alpha\dfrac{dT}{dx}[/tex]
Where q'' is the heat flux.
When This directly proportionate is remove then one constant will on that place and that constant is called conductivity of material.
[tex]q''=K\dfrac{dT}{dx}[/tex]
So total heat transfer Q
[tex]Q=KA\dfrac{dT}{dx}[/tex]
When conductivity (K) of material is not constant
K=[tex]K_0[/tex](a+bT) where a,b are constant.
So from the above expression we can say that heat transfer in material will depend on temperature difference,material property and on on geometry of object.
In shaft design, this of the following has the least influence on the shaft diameter to be determined: (a) Shaft deflection (b) Bearing type (c) Factor of safety (d) Rotational speed of the shaft
Answer: (d)Rotational speed of the shaft
Explanation: Shaft design is the design of a shaft that is used for defining the stresses at certain critical part of shaft. The shaft design has shaft diameter as a major part and this is determined by several factors like type of bearing , deflection, torque,safety factor etc.
But the least important factor for determining of the diameter is the rotational speed because it defines the rotation of an object around a particular axis, where is it states about the number of turns divisible by time. Therefore option(d) is the correct option.
Fluids at rest possess no flow energy. a)- True b)- False
Answer:
True.
Explanation:
According the engineering flow they don not possess flow energy when they are in rest.
When they are in motion they show a translation energy.
The features if fluids may be different according the variables of pressure and temperature.
Give two causes that can result in surface cracking on extruded products.
Answer:
1. High friction
2. High extrusion temperature
Explanation:
Surface cracking on extruded products are defects or breakage on the surface of the extruded parts. Such cracks are inter granular.
Surface cracking defects arises from very high work piece temperature that develops cracks on the surface of the work piece. Surface cracking appears when the extrusion speed is very high, that results in high strain rates and generates heat.
Other factors include very high friction that contributes to surface cracking an d chilling of the surface of high temperature billets.
A plate clutch is used to connect a motor shaft running at 1500rpm to shaft 1. The motor is rated at 4 hp. Using a service factor, k=2.75 specify the torque rating for the clutch in lb-in.
Answer:
[tex](M_t)_{rated}=61.11lb-in[/tex]
Explanation:
speed of motor (N)=1500 rpm
power=4 hp = [tex]4 \times 0.7457 [/tex] =2.9828 KW
service factor(k)= 2.75
now,
[tex]KW=\frac{2\pi n M_t}{60 \times 10^6} \\2.9828=\frac{2\pi \times 1500 M_t}{60 \times 10^6}\\M_t=\frac{2.9828\times 60 \times 10^6}{2\pi \times 1500 }[/tex]
[tex]M_t= 18,989.09 \ N-mm= 168.06 lb-in[/tex]
torque rating
[tex](M_t)_{design}=k_s\times (M_t)_{rated}\\168.06= 2.75\times (M_t)_{rated}\\(M_t)_{rated}=\frac{168.06}{2.75} \\(M_t)_{rated}=61.11lb-in[/tex]
A wind turbine system has the following specifications: Diameter:45 m Rated power 700 kW at the wind speed of 12 m/s Turbine speed 1500 rpm Determine the swept area of the wind turbine. a)- 1640 m^2 B)- 1690 m^2 c)- 1590 m^2 d)- 1540 m^2
Answer:
1590 m^2
Explanation:
Given data in this question
Diameter = 45 m
power = 700 kW
wind speed = 12 m/s
turbine speed = 1500 rpm
To find out
swept area of the wind turbine
Solution
we know wind turbine is rotate circular form
and diameter is given so by the area of circular swept we will calculate it
we know area = [tex]\pi /4[/tex] × d²
put the value of d here
area = [tex]\pi /4[/tex] × 45²
swept area = 1590 m^2