Conduction of electricity is by means of which individual atomic scale species? (Mark all that apply) a)- Quarks b)- Photons c)- Charge carriers d)- Wavicles e)- Klingons

Answer:

a)f=2.25 Hz

b)Time period T=.144 s

c)tex]V_{max}[/tex]=0.42 m/s

d)Phase angle Ф=87.3°

e) [tex]a_{max}=6.0041 [tex]\frac{m}{s^2}[/tex]

Explanation:

a)

Natural frequency

  [tex]\omega _n=\sqrt {\dfrac{K}{m}}[/tex]

[tex]\omega _n=\sqrt {\dfrac{150}{0.75}}[/tex]

[tex]\omega _n[/tex]=14.14 rad/s

w=2πf

⇒f=2.25 Hz

b) Time period

[tex]=\dfrac{2π}{\omega _n}[/tex]

T=[tex]\frac{1}{f}[/tex]

 Time period T=.144 s

c)Displacement equation

[tex]x=Acos\omega _nt+Bsin\omega _nt[/tex]

Boundary condition

t=o,x=0.03 m

t=0,v=.02m/s   , V=[tex]\frac{dx}{dt}[/tex]

Now by using these above conditions

A=0.03,B=0.0014

x=0.03 cos14.14 t+0.0014 sin14.14 t

⇒x=0.03003sin(14.14t+87.3)

[tex]V_{max}=\omega_n X_{max}[/tex]

[tex]V_{max}=14.14\times 0.03003[/tex]=0.42 m/s

d)

Phase angle Ф=87.3°

e)

Maximum acceleration

[tex]a_{max}=(\omega _n )^2X_{max}[/tex]

[tex]a_{max}=(14.14)^20.03003[/tex]=6.0041 [tex]\frac{m}{s^2}[/tex]

Answer:

A. 2.249 hz

B. 0.45 s

C. 0.424 m/s

D. 66⁰

E. 6 m/s^2

Explanation:

Step 1: identify the given parameters

mass of the block (m)= 0.75kg

stiffness constant (k) = 150N/m

Amplitude (A) = 3cm = 0.03m

upward velocity (v) = 2cm/s

Step 2: calculate the natural frequency (F)by applying relevant formula in S.H.M

[tex]f=\frac{1}{2\pi } \sqrt \frac{k}{m}[/tex]

[tex]f=\frac{1}{2\pi } \sqrt \frac{150}{0.75}[/tex]

f = 2.249 hz

Step 3: calculate the period of the oscillation (T)

[tex]period (T) = \frac{1}{frequency}[/tex]

[tex]T = \frac{1}{2.249} (s)[/tex]

T = 0.45 s

Step 4: calculate the maximum velocity,[tex]V_{max}[/tex]

[tex]V_{max} = A\sqrt{\frac{k}{m} }[/tex]

A is the amplitude of the oscilation

[tex]V_{max} = 0.03\sqrt{\frac{150}{0.75} }[/tex]

[tex]V_{max} = 0.424(\frac{m}{s})[/tex]

Step 5: calculate the phase angle, by applying equation in S.H.M

[tex]X = Acos(\omega{t} +\phi)[/tex]

where X is the displacement; calculated below

Displacement = upward velocity X period of oscillation

[tex]displacement (X) = vt (cm)[/tex]

X = (2cm/s) X (0.45 s)

X = 0.9 cm = 0.009m

where [tex]\omega[/tex] is omega; calculated below

[tex]\omega=\sqrt{\frac{k}{m} }[/tex]

[tex]\omega=\sqrt{\frac{150}{0.75} }[/tex]

[tex]\omega= 14.142[/tex]

[tex]\phi = phase angle[/tex]

Applying displacement equation in S.H.M

[tex]X = Acos(\omega{t}+\phi)[/tex]

[tex]0.009 = 0.03cos(14.142 X 0.45+\phi)[/tex]

[tex]cos(6.364+\phi) = \frac{0.009}{0.03}[/tex]

[tex]cos(6.364+\phi) = 0.3[/tex]

[tex](6.364+\phi) = cos^{-1}(0.3)[/tex]

[tex](6.364+\phi)= 72.5⁰[/tex]

[tex]6.364+\phi =72.5⁰[/tex]

[tex]\phi[/tex] =72.5 -6.364

[tex]\phi[/tex] =66.1⁰

Phase angle, [tex]\phi[/tex] ≅66⁰

Step 6: calculate the maximum acceleration, [tex]a_{max}[/tex]

[tex]a_{max} = \omega^{2}A[/tex]

[tex]a_{max}[/tex] = 14.142 X 14.142 X 0.03

[tex]a_{max}[/tex] = 5.999 [tex](\frac{m}{s^{2} })[/tex]

[tex]a_{max}[/tex] ≅ 6 [tex](\frac{m}{s^{2} })[/tex]

Answer:

In refrigeration cycle heat transfer from inside refrigeration

In heat pump cycle heat transfer from environment

Explanation:

heat cycle is mechanical process use for cool the temperature but

In refrigeration heat transfer from inside of refrigeration that decrease temperature of refrigerator and in heat pump it decrease temperature negligible as compare to refrigerator

Answer:

Drag Coefficient:

It is a dimensionless quantity that is used to quantify air friction or fluid friction i.e., drag and is commonly denoted by [tex]C_{d}[/ tex].It is used in Drag Equation, where a lower drag coefficient indicates that the object will have lower value of air friction or fluid friction(i.e., aerodynamic or hydrodynamic drag). It is always associated with a particular surface area.

Drag Coefficient is given by:

[tex]C_{d} = \frac{2D}{A\rho v^{2}}[/tex]

Skin Friction Coefficient:

It is a dimensionless quantity which represents skin shear stress due to dynamic pressure of a free stream.

Skin Friction Coefficient is given by:

[tex]C_{f} = \frac{2\tau _{w}}{\rho V^{2}}[/tex]

where,

[tex]\tau _{w}[/tex]= skin shear stress

v = free stream speed

Answer:

yes

Explanation:

yes, it is correct as car gets older  the engine's compression ratio changes .

compression ratio is the volume in maximum compression chamber to the volume in the piston at full compression .

More and more engine will be used if the ring wears compression goes down

or there can be one condition if carbon build up on the piston then this can alter the compression ratio.

Answer:

[tex]p=12\hat{i}+10.58\hat{j}[/tex]

Explanation:

distance of point from the origin is 16 inch

x-axis distance =12 inch

[tex]p=\sqrt{x^2+y^2[/tex]

[tex]y=\sqrt{p^2-x^2} \\y=\sqrt{16^2-12^2}\\ y=\sqrt{112}[/tex]

y=10.58 inch

[tex]p=12\hat{i}+10.58\hat{j}[/tex]

Answer: Isentropic process is the process in fluids which have a constant entropy.

Explanation: The  isentropic process is considered as the ideal thermodynamical  process and has both adiabatic as well as reversible processes in internal form.This process supports no transfer of heat and  no transformation of matter .The entropy of the provided mass also remains unchanged or consistent.These processes are usually carried out on material on  the efficient device.

Answer:

0.25 J/K

Explanation:

Given data in given question

heat (Q) = 100 J

temperature (T) = 400 K

to find out

the change in entropy of the given system

Solution

we use the entropy change equation here i.e  

ΔS = ΔQ / T           ...................a

Now we put the value of heat (Q) and Temperature (T) in equation a

ΔS is the entropy change, Q is heat and T is the temperature,  

so that

ΔS = 100/400 J/K

ΔS = 0.25 J/K

Answer:

a)COP=5.01

b)[tex]W_{in}=2.998[/tex] KW

c)COP=6.01

d)[tex]Q_R=17.99 KW[/tex]

Explanation:

Given

[tex]T_L[/tex]= -12°C,[tex]T_H[/tex]=40°C

For refrigeration

  We know that Carnot cycle is an ideal cycle that have all reversible process.

So COP of refrigeration is given as follows

[tex]COP=\dfrac{T_L}{T_H-T_L}[/tex]  ,T in Kelvin.

[tex] COP=\dfrac{261}{313-261}[/tex]

a)COP=5.01

Given that refrigeration effect= 15 KW

We know that  [tex]COP=\dfrac{RE}{W_{in}}[/tex]

RE is the refrigeration effect

So

5.01=[tex]\dfrac{15}{W_{in}}[/tex]

b)[tex]W_{in}=2.998[/tex] KW

For heat pump

So COP of heat pump is given as follows

[tex]COP=\dfrac{T_h}{T_H-T_L}[/tex]  ,T in Kelvin.

[tex] COP=\dfrac{313}{313-261}[/tex]

c)COP=6.01

In heat pump

Heat rejection at high temperature=heat absorb at  low temperature+work in put

[tex]Q_R=Q_A+W_{in}[/tex]

Given that [tex]Q_A=15[/tex]KW

We know that  [tex]COP=\dfrac{Q_R}{W_{in}}[/tex]

[tex]COP=\dfrac{Q_R}{Q_R-Q_A}[/tex]

[tex]6.01=\dfrac{Q_R}{Q_R-15}[/tex]

d)[tex]Q_R=17.99 KW[/tex]

Explanation:

(a)

The measure of material's ability to conduct thermal energy (heat) is known as thermal conductivity. For examples, metals have high thermal conductivity, it means that they are very efficient at conducting heat. The SI unit of heat capacity is W/m.K.

The expression for thermal conductivity is:

[tex]q=-\kappa \bigtriangledown T[/tex]

Where,

q is the heat flux

[tex]\kappa[/tex] is the thermal conductivity

[tex] \bigtriangledown T[/tex] is the temperature gradient.

(b)

Heat capacity for a substance is defined as the ratio of the amount of energy required to change the temperature of the substance and the magnitude of temperature change. The SI unit of heat capacity is J/K.

The expression for Heat capacity is:

[tex]C=\frac{E}{\Delta T}[/tex]

Where,

C is the Heat capacity

E is the energy absorbed/released

[tex]\Delta T[/tex] is the change in temperature

(c)

Thermal diffusivity is defined as the thermal conductivity divided by specific heat capacity at constant pressure and its density. The Si unit of thermal diffusivity is m²/s.

The expression for thermal diffusivity is:

[tex]\alpha=\frac{\kappa}{C_p \times \rho}[/tex]

Where,

[tex]\alpha[/tex] is thermal diffusivity

[tex]\kappa[/tex] is the thermal conductivity

[tex]C_p[/tex] is specific heat capacity at constant pressure

[tex]\rho[/tex] is density

Answer:

Damping ratio  [tex]\zeta =0.0342[/tex]

Explanation:

Given that

m=4.2 kg,K=85.9 N/m,C=1.3 N.s/m

We need to find damping ratio

We know that critical damping co-efficient

 [tex]C_c=2\sqrt {mk}[/tex]

 [tex]C_c=2\sqrt {4.2\times 85.9}[/tex]

 [tex]C_c=37.98[/tex] N.s/m

Damping ratio([tex]\zeta[/tex]) is the ratio of damping co-efficient to the critical damping co-efficient

So [tex]\zeta =\dfrac{C}{C_c}[/tex]

[tex]\zeta =\dfrac{1.3}{37.98}[/tex]

[tex]\zeta =0.0342[/tex]

So damping ratio  [tex]\zeta =0.0342[/tex]

Explanation:

We know that first T-ds equation

 Tds=[tex]C_v[/tex]dT+Pdv

For constant volume process dv=0

⇒Tds=[tex]C_v[/tex]dT

So [tex]\dfrac{dT}{ds}=\dfrac{T}{C_v}[/tex]          ----(1)

We know that second T-ds equation

 Tds=[tex]C_p[/tex]dT-vdP

For constant pressure process dP=0

⇒Tds=[tex]C_p[/tex]dT

So [tex]\dfrac{dT}{ds}=\dfrac{T}{C_p}[/tex]             ---(2)

We know that [tex]C_p[/tex] is always greater than [tex]C_v[/tex].

So from equation (1) and (2) we can say that slope of constant volume process will be always greater than constant pressure process on T-s diagram.

Answer:

False

Explanation:

as we know that [tex]V(x)=\frac{dM}{dx}\\ \\=> M(x) = \int\limits^x_o {V(x)} \, dx \\\\[/tex]

=> Area under shear diagram gives the moment at any point but the reverse cannot be established from the same relation

Answer:

The surface temperature is 921.95°C .

Explanation:

Given:

   a=25 cm ,P=350 hp⇒P=260750 W

Power transmitted [tex]0.95\times 260750[/tex]W and remaining will lost in the form of heat.This heat transmitted to air by the convection.

 h=230[tex]\frac{W}{m^2-K},\eta =0.95[/tex]

Actually heat will be transmit by the convection.

In convection Q=hA[tex]\Delta T[/tex]

So [tex]P=\Delta T\times Q[/tex]

[tex]0.05\times 260750=230\times0.25^2\(T-15)[/tex]

T=921.95°C

So the surface temperature is 921.95°C .

Answer:

Head loss=0.00366 ft

Explanation:

Given :Water flow rate Q=0.15 [tex]\frac{ft^{3}}{sec}[/tex]

         [tex]D_{1}[/tex]= 6 inch=0.5 ft

        [tex]D_{2}[/tex]=2 inch=0.1667 ft

As we know that Q=AV

[tex]A_{1}\times V_{1}=A_{2}\times V_{2}[/tex]

So [tex]V_{2}=\frac{Q}{A_2}[/tex]

     [tex]V_{2}=\dfrac{.015}{\frac{3.14}{4}\times 0.1667^{2}}[/tex]

     [tex]V_{2[/tex]=0.687 ft/sec

We know that Head loss due to sudden contraction

           [tex]h_{l}=K\frac{V_{2}^2}{2g}[/tex]

If nothing is given then take K=0.5

So head loss[tex]h_{l}=(0.5)\frac{{0.687}^2}{2\times 32.18}[/tex]

                                    =0.00366 ft

So head loss=0.00366 ft

Answer:0.3166N

Explanation:

Given data

Area [tex]\left ( A\right )=500 cm^2[/tex]

Gap below top plate[tex]\left ( y_1\right )=20 mm[/tex]

Gap above bottom plate[tex]\left ( y_2\right )=30 mm[/tex]

SAE 30 oil viscosity =[tex]0.38 N-s/m^2[/tex]

Velocity of middle plate[tex]\left ( v\right )=1 m/s[/tex]

There will viscous force on middle plate i.e. at above surface and below surface

Viscous force[tex]\left ( F\right )=\mu \frac{Av}{y}[/tex]

[tex]Net Force on plate F =\mu Av\left [\frac{1}{y_1} +\frac{1}{y_2}\right ][/tex]

[tex]F=0.38\times 500\times 10^{-4}\left [\frac{1}{20\times 10^{-3}} +\frac{1}{30\times 10^{-3}}\right ][/tex]

[tex]F=31.66\times 10^{-2}=0.3166 N[/tex]

this is force by oil on plate thus we need to apply atleast 0.3166N to move plate

STP stands for standard temperature pressure and NTP stands for normal temperature pressure

The maximum efficiency must be greater than the actual efficiency of the heat engine. These measurements are not reasonable.

The efficiency is defined as the work done by the engine divided by the heat supplied.

So, maximum efficiency η = 1 - T₁/T₂ = W/Qs

Where T₁ is the lower temperature and T₂ is the higher temperature.

An experimentalist claims that, based on his measurements, a heat engine receives 300 Btu of heat from a source of 900 R, converts 160 Btu of it to work, and rejects the rest as waste heat to a sink at 540 R

Substitute the value into the expression , we get

η = 1 -(540 / 900) x 100 %

η = 40 %

η  = Work done/heat supplied

Substitute the value into the expression , we get

η = 160/300 x 100 %

η = 53 %

So, the maximum efficiency must be greater than the actual efficiency of the heat engine.

Thus, these measurements are not reasonable.

Learn more about efficiency.

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The experimentalist's claim that the heat engine converts more work than allowed by the Carnot efficiency is not reasonable because it exceeds the theoretical maximum efficiency, violating the second law of thermodynamics.

The experimentalist's claim that a heat engine receives 300 Btu of heat from a source at 900 R, converts 160 Btu of it to work, and rejects the rest as waste heat to a sink at 540 R can be assessed using the second law of thermodynamics and the concept of Carnot efficiency. The Carnot efficiency can be calculated using the temperatures of the hot and cold reservoirs (Th and Tc):

Carnot Efficiency (EffC) = 1 - (Tc/Th)

Assuming the temperatures are in degrees Rankine (where 0 R is absolute zero), we can calculate the maximum theoretical efficiency for a perfectly reversible engine:

EffC = 1 - (540 R / 900 R) = 1 - 0.6 = 0.4 (or 40%)

However, the experimentalist's claim states that 160 Btu is converted to work out of the 300 Btu received, which represents an actual efficiency (EffA) of:

EffA = Work done / Heat received = 160 Btu / 300 Btu = 0.5333 (or 53.33%)

Since the actual efficiency (53.33%) claimed by the experimentalist exceeds the maximum possible Carnot efficiency (40%) for a heat engine operating between these temperatures, the experimentalist's measurements are not reasonable and violate the second law of thermodynamics.

Answer:

True.

Explanation:

Yes, zeroes indicates the precision  after the decimal point.

For smallest of the calculation in to get the precise value is very important for that the calculation can have very minute changes in decimal point as more accurate the calculation  is more zeroes will be in the decimal value .

Most of the instrument calculating weights is said to precise by how much decimal they can calculate.

Answer:

Explanation:

Using equation of pure torsion

[tex]\frac{T}{I_{polar} }=\frac{t}{r}[/tex]

where

T is the applied Torque

[tex]I_{polar}[/tex] is polar moment of inertia of the shaft

t is the shear stress at a distance r from the center

r is distance from center

For a shaft with

[tex]D_{0} =[/tex] Outer Diameter

[tex]D_{i} =[/tex] Inner Diameter

[tex]I_{polar}=\frac{\pi (D_{o} ^{4}-D_{in} ^{4}) }{32}[/tex]

Applying values in the above equation we get

[tex]I_{polar} =\frac{\pi(0.042^{4}-(0.042-.008)^{4})}{32}\\

I_{polar}= 1.74[/tex] x [tex]10^{-7} m^{4}[/tex]

Thus from the equation of torsion we get

[tex]T=\frac{I_{polar} t}{r}[/tex]

Applying values we get

[tex]T=\frac{1.74X10^{-7}X100X10^{6}  }{.021}[/tex]

T =829.97Nm

Answer: True

Explanation: Modified Reynolds Analogy is based on heat transfer process in the Plate Heat Exachanger's(PHE) which is done in the phases that have complex form plates shape by being changed into sheet metal. This analogy helps in the increment of the reliability and operation to be carried out easily in the  industries.Thus the given statement is true.

Answer:

False

Explanation:

Pascal's law is not for open container it is for enclosed fluid

Pascal's law (also known as the principle of transmission of fluid pressue)

states that when pressure is applied at any part of an enclosed fluid it is transmitted undiminished throughout the fluid as well as to the walls of the container containing the fluid i.e., change in pressure at any point in an enclosed incompressible fluid is transmitted such that the same change occurs everywhere.

Answer:

Explanation:

The functions of the following are as follows:

1). Oil Rings:

2). Fly Wheel:

3). Timing gears:

Answer: b) They comprise at least two immiscible phases

Explanation: Nano composite coating are the coating that are the mixture of one or more phases that are irregular or immiscible in nature. They are in the nano- material form which helps in the improvement of chemical as well as physical properties. The phase that are usually present in nano composite coating are of nano crystalline phase or amorphous phase or two nano crystalline phases  which are different from each other.

The efficiency of a transformer is mainly dependent on a)- Core losses

Hope this helps! :)

Answer:

e.All of the above

Explanation:

A fluid should be change

a.When its acidity increase

b.When its become contaminated

c.At operating temperature

Generally fluid is used in fluid power.Fluid power means transmission of power by using pressurized fluids.

Fluid power works on Pascal's and Bernoulli law.

From the above option we can say that all option is right for fluid  .

Answer:

V = 0.5 m/s

Explanation:

given data:

width of channel =  4 m

depth of channel = 2 m

mass flow rate = 4000 kg/s = 4 m3/s

we know that mass flow rate is given as

[tex]\dot{m}=\rho AV[/tex]

Putting all the value to get the velocity of the flow

[tex]\frac{\dot{m}}{\rho A} = V[/tex]

[tex]V = \frac{4000}{1000*4*2}[/tex]

V = 0.5 m/s

Given:

kinetic energy of free particle, KE = 35ev

1eV = [tex]1.6\times 10^{-19}[/tex] J

mass of the particle, m = [tex]2\times 10^{-26}[/tex] Kg

accuracy in velocity= 0.2%= 0.002

Solution:

a) We know that

KE = [tex]\frac{1}{2}mv^{2}[/tex]

v = [tex]\sqrt{\frac{2KE}{m}}[/tex]

⇒ v = [tex]\sqrt{\frac{2\times 35\times1.6\times 10^{-19} }{2\times 10^{-26}}}[/tex]

v = [tex]2.36\times10^{4}[/tex] m/s

b) From Heisenberg's uncertainity principle:

[tex]\Delta x\Delta p = \frac{h}{4\pi}[/tex]

[tex]\Delta x.(mv) = \frac{h}{4\pi}[/tex]

[tex]\Delta x = \frac{h}{4\pi\times 2\times 10^{-26}\times2.36 \times 10^{4}\times 0.002}[/tex]

[tex]\Delta x = 0.56nm[/tex]

Answer:

[tex]\tau_{max}= 3.28 \ MPa[/tex]

Explanation:

outside diameter = 90 mm

inside diameter = 90- 2× t=  90- 2× 5 = 80mm

where t is thickness of pipe.

power (P)  = 12 kW

Revolution (N)= 650 rev/min

we

Power = torque × angular velocity

P= T× ω

ω =  [tex]\frac{2 \pi N}{60}[/tex]

[tex]P=T \times \frac{2\pi N}{60}\\12 \times 10^3=T\times \frac{2\pi \times 650}{60}[/tex]

T=  176.3 Nm

for maximum shear stress

[tex]\frac{\tau_{max}}{y_{max}}=\frac{T}{I_p}[/tex]

where ymax is maximum distance from neutral axis.

[tex]y_{max}=\frac{d_0}{2}= \frac{90}{2}[/tex]= 45 mm

[tex]I_p[/tex]= polar moment area

          = [tex]\frac{\pi}{32} (d_o^4-d_i^4)=\frac{\pi}{32} (90^4-80^4)[/tex]

          = 2,420,008 mm⁴

[tex]\dfrac{\tau_{max}}{45}=\dfrac{176.3 \times 10^3}{2,420,008}[/tex]

[tex]\tau_{max}= 3.28 \ MPa[/tex]

Answer:

Absolute Pressure=315.06256 kPa

Explanation:

Gauge pressure= 31 psi

Atmospheric Pressure at Sea level= 1 atm=101.325 kPa

[tex]1\ psi=6.89476\ kPa\\\Rightarrow 31\ psi=31\times 6.89476\\\Rightarrow 31\ psi=213.73756\ kPa=Gauge\ Pressure\\Absolute\ Pressure=Gauge\ Pressure+Atmospheric\ Pressure\\\Rightarrow Absolute\ Pressure=213.73756+101.325\\\therefore Absolute\ Pressure=315.06256\ kPa[/tex]