Answer:
Listed Below
Explanation:
Weldability which is also known as joinability is defined as the ease with which a material can be welded without producing any other effect .
Some factors which affect weldability are
1.Melting point of metal
Higher the melting point lower will be the weldability.2.Thermal conductivity
Materials with higher thermal conductivity are difficult to join.3.Reactivity
If the material reacts with surroundings like water or air, it is difficult to weld.4.Coefficient of thermal expansion(α)
Higher the thermal expansion lower will be the weldability.5.Surface condition
The material with dirty surface is difficult to weld for example if a surface has oxide layer on it it become difficult to weld it.The two windings of transformer is: a)- Conductively linked. b)- Not linked at all. c)- Inductively linked d)- Electrically linked.
The two windings of transformer is c)- Inductively linked
Hope this helped!
Answer:
The two windings of transformer is Inductively linked -c)
A refrigeration cycle rejects Qn 500 Btu/s to a hot reservoir at 540 R, while receiving c200 Btu/s at 240°R. This refrigeration cycle a)- is internally reversible b)- is irreversible c)- is impossible d)- cannot be determined
Answer:
(b) Irreversible cycle.
Explanation:
Given;
[tex]T_2=540R ,Q_2= 500 Btu/s ,T_1=240 R ,Q_1= 200 Btu/s [/tex]
To find the validity of cycle
[tex]\oint _R\frac{dQ}{T}\leq0[/tex]
If it is zero then cycle will be reversible cycle and if it is less than zero then cycle will be irreversible cycle.These are possible cycle.
If it is greater than zero ,then cycle will be impossible .
Now find
[tex]\dfrac{Q_1}{T_1}-\dfrac{Q_2}{T_2}=\dfrac{200}{240}-\dfrac{500}{540}[/tex]
[tex]\dfrac{Q_1}{T_1}-\dfrac{Q_2}{T_2}[/tex]= -0.09
It means that this cycle is a irreversible cycle.
A smooth sphere with a diameter of 6 inches and a density of 493 lbm/ft^3 falls at terminal speed through sea water (S.G.=1.0027). Determine the terminal speed.
Given:
diameter of sphere, d = 6 inches
radius of sphere, r = [tex]\frac{d}{2}[/tex] = 3 inches
density, [tex]\rho}[/tex] = 493 lbm/ [tex]ft^{3}[/tex]
S.G = 1.0027
g = 9.8 m/ [tex]m^{2}[/tex] = 386.22 inch/ [tex]s^{2}[/tex]
Solution:
Using the formula for terminal velocity,
[tex]v_{T}[/tex] = [tex]\sqrt{\frac{2V\rho g}{A \rho C_{d}}}[/tex] (1)
[tex](Since, m = V\times \rho)[/tex]
where,
V = volume of sphere
[tex]C_{d}[/tex] = drag coefficient
Now,
Surface area of sphere, A = [tex]4\pi r^{2}[/tex]
Volume of sphere, V = [tex]\frac{4}{3} \pi r^{3}[/tex]
Using the above formulae in eqn (1):
[tex]v_{T}[/tex] = [tex]\sqrt{\frac{2\times \frac{4}{3} \pir^{3}\rho g}{4\pi r^{2} \rho C_{d}}}[/tex]
[tex]v_{T}[/tex] = [tex]\sqrt{\frac{2gr}{3C_{d}}}[/tex]
[tex]v_{T}[/tex] = [tex]\sqrt{\frac{2\times 386.22\times 3}{3C_{d}}}[/tex]
Therefore, terminal velcity is given by:
[tex]v_{T}[/tex] = [tex]\frac{27.79}{\sqrt{C_d}}[/tex] inch/sec
Define the Static Balancing.
Answer: Static Balancing is when a stationary object has the the ability to balance because its core centre of gravity is on the axis of rotation.
A motor is rated to deliver (output) 2.5 hp at 120 VDC. If the motor runs on 120 V and is 75% efficient, how many watts does it draw from the power line (input)? ( input power is always greater than output power, and remember to use a horse power conversion: 1hp =746 (watts) (a) 3.33 W (b) 1399 W (c) 1679 w (d) 2072 W (e) 2487 W
Answer:
(e) 2487 W
Explanation:
Given data
voltage = 120 V
power = 2.5 hp
efficiency = 75%
To find out
watts draw from the power line
solution
we calculate efficiency by given formula
efficiency = ( output / input ) × 100 ............1
we know our output is 2.5 hp = 2.5 × 746 = 1865 W
and efficiency is 75% = 0.75
put these value in equation 1 and find out input power
power = ( 1865 / 0.75 )
power = 2486.66 W
so our answer is (e) 2487 W
What do you think are the advantages and disadvantages of isothermal constant volume high extension cycle? And how efficient do you think it can be?
Answer Explanation :
ADVANTAGES OF ISOTHERMAL PROCESS
EASE OF MAINTENANCE: there is absence of direct contact between the combustible gas mixture and all moving part in this process LESS NOISE : These engines does not have valves so it is very simple in construction and produce less noiseBETTER PERFORMANCE : these engine have better performance than other enginesLOW TEMPERATURE : these engine can work on low temperature which is also an advantageDISADVANTAGES OF ISOTHERMAL PROCESS :
GREATER VOLUME AND GREATER WEIGHT: These engine require large volume and large weightSLOWER START: In this process the engine have very slower start which is a disadvantage HIGHER ECONOMIC COST : In this process we need more money this is also an disadvantage
When designing solid rockets, thrust and mass flow must be considered time dependent. a) True b) False
Answer:
the answer is true when designing sold rockets thrust and mass flow
What is the typical bonding in a conductor and a semiconductor??
Answer:
The typical bonding in conductors is defined as which contain free valence electrons and free ions as, it is typically known as metallic bonding. In a group of free electrons metallic ions are made up from lattice and to conduct the electricity the free electron are the main reason for ability of the metals.
On the other hand, semiconductors can be arranged as structure of lattice and also there is a covalent bonds are present.
A closed-loop system has a forward path having two series elements with transfer functions 5 and 1/(s + 1). If the feedback path has a transfer function 2/s, what is the overall transfer function of the system?
Answer:
Transfer function for feedback path is given by:
[tex]\frac{C(s)}{R(s)}[/tex]=[tex]\frac{G(s)}{1+G(s)H(s)}[/tex] (1)
Explanation:
with reference to fig1:
two blocks in series are multiplied:
[tex]\frac{5}{s(s+1)}[/tex]
for feedback function:
1+G(s)H(s)=[tex]1+\frac{5}{s+1}.\frac{2}{s}[/tex]
Now from eqn (1):
[tex]\frac{C(s)}{R(s)} = \frac{5}{s(s+1)+10}[/tex]
Heat in the amount of 100 kJ is transferred directly from a hot reservoir at 1200 K to a cold reservoir at 600 K. Calculate the entropy change of the two reservoirs and determine if the increase of entropy principle is satisfied.
Solution:
Given:
[tex]T_{H}[/tex] = 1200 K
[tex]T_{L}[/tex] = 600 K
Q = 100 kJ
The Entropy change of the two reservoirs is given by the sum of entropy change of each reservoir system and is given by the formula:
[tex]\Delta s = \frac{-Q}{T_{H}}+\frac{Q}{T_{L}}[/tex]
[tex]\Delta s = \frac{Q(T_{L}-T_{_{H}})}{T_{H}T_{L}}[/tex]
[tex]\Delta s = \frac{-100(600-1200)}{1200\times 600}[/tex]
[tex]\Delta s = 0.0833kJ/K
Since, the change in entropy is positive and according to the Increase in entropy principle, for any process the total change in entropy of a system is always greater than or equal to zero (with its enclosing adiabatic surrounding).
Therefore, the entropy principle is satisfied.
_____What is matrix in tungsten carbide cutting tool? a)- Chromium b)- Manganese c)- Cobalt d)- Aluminum
Answer:
The correct option is C) Cobalt
Explanation:
The cemented carbides are hard substances which are extensively used as cutting tools materials. In the cemented carbides, substances like tungsten-carbide are used as aggregates.
A tungsten carbide- cobalt cutting tool is a metal matrix composite, in which the tungsten carbide is the aggregate and the cobalt is the matrix.
Therefore, in the tungsten carbide cutting tool, cobalt is used as the matrix.
The purifier is a device in a)- The air separation plant b)- steam power plant c)-- fuel cell d)- refrigerator
Answer:
a). Air separation plant
Explanation:
The purifier is a device that removes the pollutants or air contaminants from air to improve the air quality in a given space.
There are basically two techniques or ways by which the air purifier makes the air contaminants free. This two techniques are active and passive.
Active air purifiers : negatively charged ions are released to the atmosphere which sticks the pollutants to the surface.
Passive air purifiers : They use air filters to eliminate pollutants and are more efficient than an active air purifiers.
Answer:
(A) Air separation plant
Explanation:
Purifier is used in air separation plant to purify the air main work of purifier is to remove the pollutants particles from the air and make the air fresh.
On the other hand it has no use team power pant because in steam power plant we don't need to purify the steam and also not used in fuel cell and refrigerator
So purifiers are used in the air separation plant.
Proper grain stress/strain analysis is required in solid motor design: A. To ensure good motor structure B. To avoid surface cracks C. To avoid bond separation D. All of the above
Answer:
The correct answer to the given statement is
option D. All of the above
Explanation:
Analysis of proper grain stress/strain is important as it ensures good mechanical motor structure.
With the help of analysis surface cracks can be checked and proper maintenance can be provided. It further helps in keeping check in order to avoid separation of bonds.
Therefore, qualitative analysis and in depth analysis can reduce errors and helps to maintain the qualitative parameters.
What is a Mollier diagram?
Answer: Mollier diagram is the diagram or graph representing the relation established between enthalpy ,air, moisture and temperature.
Explanation: Mollier graph represents the basic thermodynamic properties along with terms of enthalpy and entropy. The factors like air, moisture , temperature etc. are plotted on the graph which makes it easy to understand. It is used in the field building designers and engineer.They are usually plotted for the gases with purity with general pressure and temperature.
The thermal efficiency of two reversible power cycles operating between the same thermal reservoirs will a)- depend on the mechanisms being used b)- be equal regardless of the mechanisms being used c)- be less than the efficiency of an irreversible power cycle
In a steady flow device, the properties of the system remains constant with time. a)True b) False
Answer:
True
Explanation:
By definition of steady flow we have
[tex]\frac{\partial f(x,y,z,t) }{\partial t}=0[/tex]
where f(x,y,z,t) is any property of the system under consideration
=> f(x,y,z,t) = constant
-Pure substance at sublimation line exist as a mixture of liquid and solid(____)
Answer:
False
Explanation:
A graphical representation of transition of substance's physical state under various temperature and pressure conditions is known as phase diagram.
A typical phase diagram usually consists of:
(A) Fusion curve - The curve that represents that the solid and the liquid state exists in the equilibrium with each other is called fusion curve.
(B) Vaporization curve - The curve that represents that the liquid and the gaseous state exists in the equilibrium with each other is called fusion curve.
(C) Sublimation curve - The curve that represents that the solid and the gaseous state exists in the equilibrium with each other is called fusion curve.
(D) Triple point - This is a point in the phase diagram in which all the three state exists in equilibrium.
Thus, for a pure substance, sublimation line exist as a mixture of solid and gas. The statement is false.
A Carnot machine operates with 25% efficiency, whose heat rejection reservoir temperature is 300K. Determine the temperature at which the machine absorbs heat.
Answer:
The temperature at which observed heat is 400 K
Explanation:
Given data:
rejection reservoir temperature at exit [tex]T_{L}[/tex] is 300 k
the efficiency of a engine is η = 25%
we know that efficiency of Carnot is given as
[tex]\eta = (1-\frac{T_{L}}{T_{H}})*100[/tex]
Putting all value to obtained temperature at which observed heat
[tex]0.25 = (1-\frac{300}{T_{H}})[/tex]
[tex]T_{H}[/tex] = 400 K
What is the Principle of Entropy Increase?
Answer and Explanation:
The increase in entropy principle is defined as the process in which the total change in entropy of system with its adiabatic surroundings is always positive or equal to zero. The increase in entropy mostly takes place when a solid becomes liquid because randomness is increases when solid becomes liquid so entropy is also increases.
example of increase of entropy is when solid burns and become ash, ice melting
What is flow energy? Do fluids at rest possess any flow energy?
Flow energy is the energy possessed by a fluid due to its motion, which is quantified by kinetic energy density. Based on Bernoulli's equation, fluids at rest do not have flow energy but can have potential energy. The total mechanical energy of a fluid includes potential and kinetic energy components.
Explanation:Flow energy refers to the energy that fluid possesses due to its motion. This form of energy can be described by kinetic energy density, which is part of the total mechanical energy in a flowing fluid. According to Bernoulli's equation, the total mechanical energy of a fluid is composed of potential energy and kinetic energy. The kinetic energy of the fluid relates to its velocity and is expressed as (1/2)ρV^2, where ρ is the density of the fluid and V is the fluid velocity. On the other hand, fluids at rest do not possess flow energy or kinetic energy related to movement, but they can still have potential energy due to their position.
According to conservation of energy principles, the work done by the fluid's pressure changes the fluid's kinetic and potential energies, per unit volume. No additional flow energy is present in a fluid at rest; however, it may still exert pressure at the bottom of a container or well due to its potential energy.
A 9-cm diameter, 11-cm high hollow metal can floats in water vertically with 8 cm of its height under water. What is the weight of the can?
Answer:
Weight of the can is 5 N
Explanation:
The weight of the can is a downward force. When an object floats in a fluid, it is acted upon by an upward force which balances the weight of the body that acts downwards. This upward force is know as Buoyant force. This buoyant force is also the weight of the fluid displaced by the object.
Therefore, we know that
Total buoyant force = total weight of the body
And total weight of the body is nothing but the weight of the fluid displaced by the body.
So, weight of the body = weight of the fluid displaced by the body.
= [tex]\rho g\times[/tex]volume of water displaced by the body.
= [tex]\rho g\times[/tex]volume of the body submerged in the water
Now we know that,
density of water, [tex]\rho[/tex] = 1000 kg/[tex]m^{3}[/tex]
acceleration due to gravity, g = 9.81 m/[tex]s^{2}[/tex]
Volume of the body submerged in water, V = [tex]\frac{\prod }{4}\times d^{2}\times h[/tex]
= [tex]\frac{\prod }{4}\times 0.09^{2}\times 0.08[/tex]
= 5.05[tex]\times 10^{-4}[/tex] [tex]m^{3}[/tex]
Therefore, weight of can = [tex]\rho g\times[/tex]volume of the body submerged in the water
= 1000[tex]\times 9.81\times 5.05\times 10^{-4}[/tex]
= 4.95 N
[tex]\simeq[/tex] 5 N
Therefore the weight of the can is 5 N.
A flywheel accelerates for 5 seconds at 2 rad/s2 from a speed of 20 rpm. Determine the total number of revolutions of the flywheel during the period of its acceleration. a.5.65 b.8.43 c. 723 d.6.86
Answer:
option (a)
Explanation:
t = 5 sec, α = 2 rad/s^2, f0 = 20 rpm = 20 / 60 rps
Use second equation of motion for rotational motion
θ = ω0 x t + 1/2 α t^2
θ = 2 x 3.14 x 5 x 20 / 60 + 0.5 x 2 x 5 x 5
θ = 10.47 + 25 = 35.47 rad
Number of revolution = 35.47 / (2 x 3.14) = 5.65
What is the temperature dependency of the electrical conductivity for metals and semiconductors??
Answer and Explanation:
TEMPERATURE DEPENDENCY ON ELECTRICAL CONDUCTIVITY OF METALS : Metals are good conductors of electricity but when we increase the temperature the free electrons of metals collide with each other due to heat.There collision become very fast and so the resistance increases and so the electrical conductivity of metals decreases on increasing temperature.
TEMPERATURE DEPENDENCY ON ELECTRICAL CONDUCTIVITY OF SEMICONDUCTOR : The electrical conductivity of semiconductor is mainly sue to presence of impurities and defects as the temperature increases the impurities and defects also increases so the electrical conductivity of semiconductor increases on increasing temperature.
It is true about Metals and alloys: a)-They are good electrical and thermal conductors b)-They can be used as semi-conductors c)-They present high modulus of elasticity d)-a and c are correct
Answer:
(d) a and c are correct
Explanation:
METALS : Metal are those materials which has very high ductility, high modulus of elasticity, good thermal and electrical conductivity
for example : iron, gold ,silver, copper
ALLOYS: Alloys are those materials which are made up of combining of two or more than two metals these also have good thermal and electrical conductivity and me liable property
for example ; bronze and brass
so from above discussion it is clear that option (d) will be the correct option
Answer:
d)-a and c are correct
Explanation:
Hello,
As long as metals have specific molecular arrangements (closely assembled molecules) they have a high capacity to transfer both electrical and thermal energy. On the other hand, the modulus of stability is considered as a measure of material's stiffness or resistance to elastic deformation, thus, due to the very same aforesaid molecular arrangement of metals, they are hard to deform so that modulus is considered as high.
Best regards.
Oil with a density of 800 kg/m3 is pumped from a pressure of 0.6 bar to a pressure of 1.4 bar, and the outlet is 3 m above the inlet. The volumetric flow rate is 0.2 m3/s, and the inlet and exit areas are 0.06 m2 and 0.03 m3, respectively. (a) Assuming the temperature to remain constant and neglecting any heat transfer, determine the power input to the pump in kW. (b) What-if Scenario: What would the necessary power input be if the change in KE were neglected in the analysis??
Answer:
23.3808 kW
20.7088 kW
Explanation:
ρ = Density of oil = 800 kg/m³
P₁ = Initial Pressure = 0.6 bar
P₂ = Final Pressure = 1.4 bar
Q = Volumetric flow rate = 0.2 m³/s
A₁ = Area of inlet = 0.06 m²
A₂ = Area of outlet = 0.03 m²
Velocity through inlet = V₁ = Q/A₁ = 0.2/0.06 = 3.33 m/s
Velocity through outlet = V₂ = Q/A₂ = 0.2/0.03 = 6.67 m/s
Height between inlet and outlet = z₂ - z₁ = 3m
Temperature to remains constant and neglecting any heat transfer we use Bernoulli's equation
[tex]\frac {P_1}{\rho g}+\frac{V_1^2}{2g}+z_1+h=\frac {P_2}{\rho g}+\frac{V_2^2}{2g}+z_2\\\Rightarrow h=\frac{P_2-P_1}{\rho g}+\frac{V_2^2-V_1^2}{2g}+z_2-z_1\\\Rightarrow h=\frac{(1.4-0.6)\times 10^5}{800\times 9.81}+\frac{6.67_2^2-3.33^2}{2\times 9.81}+3\\\Rightarrow h=14.896\ m[/tex]
Work done by pump
[tex]W_{p}=\rho gQh\\\Rightarrow W_{p}=800\times 9.81\times 0.2\times 14.896\\\Rightarrow W_{p}=23380.8\ W[/tex]
∴ Power input to the pump 23.3808 kW
Now neglecting kinetic energy
[tex]h=\frac{P_2-P_1}{\rho g}+z_2-z_1\\\Righarrow h=\frac{(1.4-0.6)\times 10^5}{800\times 9.81}+3\\\Righarrow h=13.19\ m\\[/tex]
Work done by pump
[tex]W_{p}=\rho gQh\\\Rightarrow W_{p}=800\times 9.81\times 0.2\times 13.193\\\Rightarrow W_{p}=20708.8\ W[/tex]
∴ Power input to the pump 20.7088 kW
Consider three identical items in parallel. What is the system reliability if each item has a reliability of 98%?
Answer:
Reliability of system = 99.9992%
Explanation:
Given Reliability of item = 98%
therefore probability of failure = 100%-98% =2%
For system in parallel the probability of failure is product of individual probabilities of items
thus
[tex]Probabilityfail_{system}=p_{1}\times p_{2}\times p_{3}\\\\Probabilityfail_{system}=0.02^{3}=0.000008\\\\Realibility_{system}=100- Probabilityfail_{system}\\\\Realibility_{system}=99.9992%[/tex]
Just-in-time delivery is not an important component of Lean manufacturing. a)- True b)- False
Answer:
False
Explanation:
Just-in-time manufacturing means that production is done when there is demand. It is a pull system which means that demand dictates production. Lean manufacturing is method of production which aims to reduce the seven types of waste which are
Logistics
Inventory
Motion of objects during manufacturing
Unnecessary delay
Producing more than demand
Over Processing of goods
Malfunctioning items.
Here it can be seen that Producing more than demand is a waste. This can be reduced by Just in Time manufacturing.
Are spheroidized steels considered as composite? If so, what is the dispersed phase a)- No b)- Yes, Chromium Carbides c)- Yes, Iron Carbides d)- Yes, Intermetallic Compounds
Answer: c)-Yes, spheroidized steel are considered as composite.the dispersed phase is iron carbide.
Explanation: Spheroidized steel are the alloy that have iron as the basic part that have been heat treated to increase their ductility and malleability property .They are considered as composite because they are made up of iron alloys. The heat treatment is usually for the carbon steel and so the dispersed phase that is obtained is iron carbide.
A rigid, sealed tank initially contains 2000 kg of water at 30 °C and atmospheric pressure. Determine: a) the volume of the tank (m3 ). Later, a pump is used to extract 100 kg of water from the tank. The water remaining in the tank eventually reaches thermal equilibrium with the surroundings at 30 °C). Determine: b) the final pressure (kPa).
Given:
mass of water, m = 2000 kg
temperature, T = [tex]30^{\circ}C[/tex] = 303 K
extacted mass of water = 100 kg
Atmospheric pressure, P = 101.325 kPa
Solution:
a) Using Ideal gas equation:
PV = m[tex]\bar{R}[/tex]T (1)
where,
V = volume
m = mass of water
P = atmospheric pressure
[tex]\bar{R} = \frac{R}{M} [/tex]
R= Rydberg's constant = 8.314 KJ/K
M = molar mass of water = 18 g/ mol
Now, using eqn (1):
[tex]V = \frac{m\bar{R}T}{P}[/tex]
[tex]V = \frac{2000\times \frac{8.314}{18}\times 303}{101.325}[/tex]
[tex]V = 2762.44 m^{3}[/tex]
Therefore, the volume of the tank is [tex]V = 2762.44 m^{3}[/tex]
b) After extracting 100 kg of water, amount of water left, m' = m - 100
m' = 2000 - 100 = 1900 kg
The remaining water reaches thermal equilibrium with surrounding temperature at T' = [tex]30^{\circ}C[/tex] = 303 K
At equilibrium, volume remain same
So,
P'V = m'[tex]\bar{R}[/tex]T'
[tex]P' = \frac{1900\times \frac{8.314}{18}\times 303}{2762.44}[/tex]
Therefore, the final pressure is P' = 96.258 kPa
What does WCS stand for? A. Western CAD System B. Worldwide Coordinate Sectors C. World Coordinate System D. Wrong CAD Settings
Answer:
The correct answer is C. World Coordinate System
Explanation:
The World Coordinate System has to do with that coordinate system which is fixed in the activities of the CADing. There is a default system in which we can refer to them as soon as we want to manipulate the objects and add new elements.