Before cutting coarse screw threads, the operator should lubricate: A. The leadscrew and gearbox B. The ways and cross slide C. The carriage and half-nuts D. A1l of the above

Answers

Answer 1

Answer:

(d) all of the above

Explanation:

before cutting the screw threads the operator should lubricate all of the machine parts given in the option that is lead screw and gearbox , the ways and the cross slide and the carriage and half-nuts. we should use lubrication because it reduces the overall system friction and if friction is reduced then heat generated due to friction is also decreases which is beneficial

so option (D) will be correct because we need lubricate in all the given parts  


Related Questions

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.

Answers

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.

A container filled with a sample of an ideal gas at the pressure of 150 Kpa. The gas is compressed isothermally to one-third of its original volume. What is the new pressure of the gas a)-900 kpa b)- 300 kpa c)- 450 kpa d)- 600 kpa

Answers

Answer: c) 450 kPa

Explanation:

Boyle's Law: This law states that pressure is inversely proportional to the volume of the gas at constant temperature and number of moles.

[tex]P\propto \frac{1}{V}[/tex]     (At constant temperature and number of moles)

[tex]P_1V_1=P_2V_2[/tex]  

where,

[tex]P_1[/tex] = initial pressure of gas  = 150 kPa

[tex]P_2[/tex] = final pressure of gas  = ?

[tex]V_1[/tex] = initial volume of gas   = v L

[tex]V_2[/tex] = final volume of gas  = [tex]\frac{v}{3}L[/tex]

[tex]150\times v=P_2\times \frac{v}{3}[/tex]  

[tex]P_2=450kPa[/tex]

Therefore, the new pressure of the gas will be 450 kPa.

The melting point of W (tungsten) is 3380°C, is the processing at 1100 C hot working or cold working?

Answers

Answer:

cold working

Explanation:

Given data in question

melting point tungsten (W) = 3380°C = 3653 K

processing temperature = 1100°C = 1373 K

To find out

process is hot or cold working

solution

we know hot working and cold working process is depend upon the Recrystallization and Recrystallization is a process in which deformed grains of crystal structures are replace with stress-free grains that nucleate and grow till actual grains have been consumed fully

and we know that ratio of processing temperature and melting point tungsten is greater than 60% than the process is start of Recrystallization so we check ratio

ratio =  processing temperature / melting point tungsten

ratio =  1373 / 3653

ratio = 0.3758 = 37.58 %

we can see this is less than 60 % so our process is cold working

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).

Answers

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

In thermodynamicsedependent properties means?

Answers

Answer:

Explanation:

Thermodynamics properties are the properties which defined the state of any system.

some of the thermodynamics properties are pressure, temperature etc

thermodynamics are broadly divided into two type

1)intensive and

2)extensive properties

Dependent properties are the properties that are dependent on other properties. Extensive property are those which are dependent on the extent of system. Example volume. if size of the system increase or decrease then volume also have same effect according to the changes

A direct contact heat exchanger (where the fluid mixes completely) has three inlets and one outlet. The mass flow rates of the inlets are 1kg/s, 1.5kg/s and 2 kg/s. The enthalpy of those inlets are the 100kJ/kg, 120kJ/kg, and 500kJ/kg, respectively. What is the enthalpy at the outlet?

Answers

Answer:

Enthalpy at outlet=284.44 KJ

Explanation:

[tex]m_1=1 Kg/s,m_2=1.5 Kg/s,m_3=22 Kg/s[/tex]

[tex]h_1=100 KJ/Kg,h_2=120 KJ/Kg,h_3=500 KJ/Kg[/tex]

We need to Find enthalpy of outlet.

Lets take the outlet mass m and outlet enthalpy h.

So from mass conservation

[tex]m_1+m_2+m_3=m[/tex]

   m=1+1.5+2 Kg/s

  m=4.5 Kg/s

Now from energy conservation

[tex]m_1h_1+m_2h_2+m_3h_3=mh[/tex]

By putting the values

[tex]1\times 100+1.5\times 120+2\times 500=4.5\times h[/tex]

So h=284.44 KJ

The two windings of transformer is: a)- Conductively linked. b)- Not linked at all. c)- Inductively linked d)- Electrically linked.

Answers

The two windings of transformer is c)- Inductively linked

Hope this helped!

Answer:

The two windings of transformer is Inductively linked -c)

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.

Answers

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

A piston-cylinder assembly has initially a volume of 0.3 m3 of air at 25 °C. Mass of the air is 1 kg. Weights are put on the piston until the air reaches to 0.1 m3 and 1,000 °C, in which the air undergoes a polytropic process (PV" const). Assume that heat loss from the cylinder, friction of piston, kinetic and potential effects are negligible. 1) Determine the polytropic constant n. 2) Determine the work transfer in ki for this process, and diseuss its direction. 3) sketch the process in T-V (temperature-volume) diagram.

Answers

Answer:

n=2.32

w= -213.9 KW

Explanation:

[tex]V_1=0.3m^3,T_1=298 K[/tex]

[tex]V_2=0.1m^3,T_1=1273 K[/tex]

Mass of air=1 kg

For polytropic process  [tex]pv^n=C[/tex] ,n is the polytropic constant.

  [tex]Tv^{n-1}=C[/tex]

  [tex]T_1v^{n-1}_1=T_2v^{n-1}_2[/tex]

[tex]298\times .3^{n-1}_1=1273\times .1^{n-1}_2[/tex]

n=2.32

Work in polytropic process given as

       w=[tex]\dfrac{P_1V_1-P_2V_2}{n-1}[/tex]

      w=[tex]mR\dfrac{T_1-T_2}{n-1}[/tex]

Now by putting the values

w=[tex]1\times 0.287\dfrac{289-1273}{2.32-1}[/tex]

w= -213.9 KW

Negative sign indicates that work is given to the system or work is done on the system.

For T_V diagram

  We can easily observe that when piston cylinder reach on new position then volume reduces and temperature increases,so we can say that this is compression process.

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??

Answers

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

What is the temperature dependency of the electrical conductivity for metals and semiconductors??

Answers

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.

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?

Answers

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.

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

Answers

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.

A dielectric is an insulating material or a very poor conductor of electric current. (True , False )

Answers

True.

Dielectric is a material with a low electrical conductivity (σ << 1); that is, an insulator, which has the property of forming electric dipoles inside it under the action of an electric field. Thus, all dielectric materials are insulators but not all insulating materials are dielectric.

Some examples of this type of materials are glass, ceramics, rubber, mica, wax, paper, dry wood, porcelain, some fats for industrial and electronic use and bakelite. As for the gases, the air, nitrogen and sulfur hexafluoride are used as dielectrics.

What do you understand by the term redundant work?

Answers

Answer:

 Redundant work refers to the work done during the process of deformation due to friction. It happens during the wire drawing. Redundant work per unit volume increases when the radial position becomes higher. The redundant work factor is defined as increased strain of the deformation to the stress. It is basically related to the deformation area geometry.

What is the typical bonding in a conductor and a semiconductor??

Answers

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 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

Answers

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

The interactions between a closed system and its surroundings include energy transfer by heat, boundary work and flow work. a)True b) False

Answers

Answer:

b) False

Explanation:

In close system only energy transfer take place and mass transfer is zero.But on the other hand in open system energy as well mass transfer take place.

Energy transfer means work as well as heat transfer.But we know that in close system there is no any flow of mass so there will not be any flow work,only boundary work will associated with close system.But in open system flow work take place.

A diesel engine with CR= 20 has inlet at 520R, a maximum pressure of 920 psia and maximum temperature of 3200 R. With cold air properties find the cutoff ratio, the expansion ratio v4/v3, and the exhaust temperature.

Answers

Answer:

Cut-off ratio[tex]\dfrac{V_3}{V_2}=6.15[/tex]

Cxpansion ratio[tex]\dfrac{V_4}{V_3}=3.25[/tex]

The exhaust temperature[tex]T_4=1997.5R[/tex]

Explanation:

Compression ratio CR(r)=20

[tex]\dfrac{V_1}{V_2}=20[/tex]

[tex]P_2=P_3=920 psia[/tex]

[tex]T_1=520 R ,T_{max}=T_3,T_3=3200 R[/tex]

We know that for air γ=1.4

If we assume that in diesel engine all process is adiabatic then

[tex]\dfrac{T_2}{T_1}=r^{\gamma -1}[/tex]

[tex]\dfrac{T_2}{520}=20^{1.4 -1}[/tex]

[tex]T_2=1723.28R[/tex]

[tex]\dfrac{V_3}{V_2}=\dfrac{T_3}{T_2}[/tex]

[tex]\dfrac{V_3}{V_2}=\dfrac{3200}{520}[/tex]

So cut-off ratio[tex]\dfrac{V_3}{V_2}=6.15[/tex]

[tex]\dfrac{V_1}{V_2}=\dfrac{V_4}{V_3}\times\dfrac{V_3}{V_2}[/tex]

Now putting the values in above equation

[tex]\dfrac20=\dfrac{V_4}{V_3}\times 6.15[/tex]

[tex]\dfrac{V_4}{V_3}=3.25[/tex]

So expansion ratio[tex]\dfrac{V_4}{V_3}=3.25[/tex].

[tex]\dfrac{T_4}{T_3}=(expansion\ ratio)^{\gamma -1}[/tex]

[tex]\dfrac{T_3}{T_4}=(3.25)^{1.4 -1}[/tex]

[tex]T_4=1997.5R[/tex]

So the exhaust temperature[tex]T_4=1997.5R[/tex]

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?

Answers

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]

With increases in magnification, which of the following occur? a. The field of view decreases. b. The ambient illumination decreases. c. The larger parts can be measured. d. The eyepiece must be raised.

Answers

By increasing magnification you decrease the field of view.

The answer is A.

Hope this helps.

r3t40

A piston-cylinder device contains 1.329 kg of nitrogen gas at 120 kPa and 27 degree C. The gas is now compressed slowly in a polytropic process during which PV^1.49 = constant. The process ends when the volume is reduced by one-half. Determine the entropy change of nitrogen during this process.

Answers

Answer:-0.4199 J/k

Explanation:

Given data

mass of nitrogen(m)=1.329 Kg

Initial pressure[tex]\left ( P_1\right )[/tex]=120KPa

Initial temperature[tex]\left ( T_1\right )=27\degree \approx[/tex] 300k

Final volume is half of initial

R=particular gas constant

Therefore initial volume of gas is given by

PV=mRT

V=0.986\times 10^{-3}

Using [tex]PV^{1.49}[/tex]=constant

[tex]P_{1}V^{1.49}[/tex]=[tex]P_2\left (\frac{V}{2}\right )[/tex]

[tex]P_2[/tex]=337.066KPa

[tex]V_2[/tex]=[tex]0.493\times 10^{-3} m^{3}[/tex]

and entropy is given by

[tex]\Delta s[/tex]=[tex]C_v \ln \left (\frac{P_2}{P_1}\right )[/tex]+[tex]C_p \ln \left (\frac{V_2}{V_1}\right )[/tex]

Where, [tex]C_v[/tex]=[tex]\frac{R}{\gamma-1}[/tex]=0.6059

[tex]C_p[/tex]=[tex]\frac{\gamma R}{\gamma -1}[/tex]=0.9027

Substituting values we get

[tex]\Delta s[/tex]=[tex]0.6059\times\ln \left (\frac{337.066}{120}\right )[/tex]+[tex]0.9027 \ln \left (\frac{1}{2}\right )[/tex]

[tex]\Delta s[/tex]=-0.4199 J/k

Consider three identical items in parallel. What is the system reliability if each item has a reliability of 98%?

Answers

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

Answers

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.

When designing solid rockets, thrust and mass flow must be considered time dependent. a) True b) False

Answers

Answer:

the answer is true when designing sold rockets thrust and mass flow

Define the various properties and constraints that ensure weldability/joinability.

Answers

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.

At winter design conditions, a house is projected to lose heat at a rate of 60,000 Btu/h. The internal heat gairn from people, lights, and appliances is estimated to be 6000 Btuh Ifthis house is to be heated by electric resistance heaters, determine the required rated power of these heaters in kW to maintain the house at constant temperature.

Answers

Answer:

15.8529 kW

Explanation:

Rate of heat loss = 60000 Btu/h

Internal heat gain = 6000 Btu/h

Rate of heat required to be supplied

[tex]P_{Sup}=\text{Rate of heat loss}-\text{Internal heat gain}\\\Rightarrow P_{Sup}=60000-6000\\\Rightarrow P_{Sup}=54000\ Btu/h[/tex]

Converting 54000 Btu/h to kW (kJ/s)

1 Btu = 1.05506 kJ

1 h = 3600 s

[tex]P_{Sup}=54000\times \frac{1.05506}{3600}\\\Rightarrow P_{Sup}=15.8529\ kW[/tex]

∴ Required rated power of these heaters is 15.8529 kW

Answer:

Q = 15.8 kW

Explanation:

Given data:

Heat loss rate is 60,000 Btu/h

Heat gain is 6000 Btu/h

Rate of heat required is computed as

Q = (60000 - 6000) Btu/h

Q = 54000 Btu/h

change Btu/h to Kilo Watts

[tex]Q = 54000 Btu/h (\frac{1W}{3.412142\ Btu/h})[/tex]

[tex]Q = 15825.8 W(\frac{1 kW}{1000 W})[/tex]

Q = 15.8 kW

Define the Static Balancing.

Answers

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.

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

Answers

c ,, i’m pretty sure .

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

Answers

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.

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