Identify the correct statements in the context of friction factors of laminar and turbulent flows
a) In turbulent flow, the tubes with rough surfaces have much higher friction factors than the tubes with smooth surfaces
b) In turbulent flow, the tubes with rough surfaces have much lower friction factors than the tubes with smooth surfaces.
c) In laminar flow, the friction factor is dependent on the surface roughness
d) In laminar flow, the friction factor is independent of the surface roughness.

Answer:

α = kt

ω = [tex]\frac{kt^2}{2}[/tex]

θ = [tex]\frac{kt^3}{6}[/tex]  

Explanation:

given data

Initial velocity ω = 0

time t = 10 s

Number of revolutions = 20

solution

we will take here first α = kt     .....................1

and as α = [tex]\frac{d\omega}{dt}[/tex]

so that

[tex]\frac{d\omega}{dt}[/tex] = kt      ..................2

now we will integrate it then we will get

∫dω  = [tex]\int_{0}^{t} kt\ dt[/tex]   .......................3

so

ω = [tex]\frac{kt^2}{2}[/tex]

and

ω = [tex]\frac{d\theta}{dt}[/tex]     ..............4

so that

[tex]\frac{d\theta}{dt}[/tex]  = [tex]\frac{kt^2}{2}[/tex]

now we will integrate it then we will get

∫dθ = [tex]\int_{0}^{t}\frac{kt^2}{2} \ dt[/tex]      ...............5

solve it and we get

θ = [tex]\frac{kt^3}{6}[/tex]  

Answer:

Option C = internal energy stays the same.

Explanation:

The internal energy will remain the same or unchanged because this question has to do with a concept in physics or classical chemistry (in thermodynamics) known as Free expansion.

So, the internal energy will be equals to the multiplication of the change in temperature, the heat capacity (keeping volume constant) and the number of moles. And in free expansion the internal energy is ZERO/UNCHANGED.

Where, the internal energy, ∆U = 0 =quantity of heat, q - work,w.

The amount of heat,q = Work,w.

In the concept of free expansion the only thing that changes is the volume.

Answer:

The final volumetric flow rate will be "76.4 m³/s".

Explanation:

The given values are:

[tex]\dot{m_{1}}=10 \ kg/s[/tex]

[tex]\dot{m_{2}}=20 \ Kg/s[/tex]

[tex]T_{1}=293 \ K[/tex]

[tex]T_{2}=313 \ K[/tex]

[tex]P_{1}=P_{2}=P_{3}=10 \ bar[/tex]

As we know,

⇒  [tex]E_{in}=E_{out}[/tex]

[tex]\dot{m_{1}}h_{1}+\dot{m_{2}}h_{2}=\dot{m_{3}}h_{3}[/tex]

[tex]e_{1}\dot{v_{1}}h_{1}+e_{2}\dot{v_{2}}h_{2}=e_{3}\dot{v_{3}}h_{3}[/tex]

[tex]\frac{P_{1}}{RP_{1}}\dot{v_{1}} \ C_{p}T_{1}+ \frac{P_{2}}{RP_{2}}\dot{v_{2}} \ C_{p}T_{1}=\frac{P_{3}}{RP_{3}}\dot{v_{3}} \ C_{p}T_{3}[/tex]

⇒  [tex]\dot{v_{3}}=\dot{v_{1}}+\dot{v_{2}}[/tex]

         [tex]=\frac{\dot{m_{1}}}{e_{1}}+\frac{\dot{m_{2}}}{e_{2}}[/tex]

On substituting the values, we get

         [tex]=\frac{10}{10\times 10^5}\times 8314\times 293+\frac{20\times 8314\times 313}{10\times 10^5}[/tex]

         [tex]=76.4 \ m^3/s[/tex]