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3 years ago

In a reversible process both the system and surrondings can be returned to their initial states. a)-True b)-False

Engineering

1 answer:

Nuetrik [128]3 years ago

6 0

Answer:

a)-True

Explanation:

When the direction of a process is reversed through infinitesimal changes to the system. The infinitesimal changes are done by the surroundings. After the process has been reversed the system and surroundings go back to their original state.

The changes take an infinite amount of time so, it is not possible practically.

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It is desired to produce and aligned carbon fiber-epoxy matrix composite having a longitudinal tensile strength of 630 MPa. Calc

ratelena [41]

Answer:

The answer is below

Explanation:

Given that:

Diameter (D) = 0.03 mm = 0.00003 m, length (L) = 2.4 mm = 0.0024 m, longitudinal tensile strength $(\sigma_{cd})=630\ MPa = 630*10^6\ Pa$ , Fracture strength

$(\sigma_f)=5100\ MPa=5100*10^6\ Pa,fiber-matrix\ stres(\sigma_m)=17.5\ MPa=17.5*10^6\ Pa,matrix\ strength=\tau_c=17\ MPa=17 *10^6\ Pa$

a) The critical length ( $L_c$ ) is given by:

$L_c=\sigma_f*(\frac{D}{2*\tau_c} )=5100*10^6*\frac{0.00003}{2*17*10^6}=0.0045\ m=4.5\ mm$

The critical length (4.5 mm) is greater than the given length, hence th composite can be produced.

b) The volume fraction (Vf) is gotten from the formula:

$\sigma_{cd}=\frac{L*\tau_c}{D}*V_f+\sigma_m(1-V_f)\\\\V_f=\frac{\sigma_{cd}-\sigma_{m}}{\frac{L*\tau_c}{D}-\sigma_{m}} \\\\Substituting:\\\\V_f=\frac{630*10^6-17.5*10^6}{\frac{0.0024*17*10^6}{0.00003} -17.5*10^6} \\\\V_f=0.456$

6 0

3 years ago

Give five general principles involved in the process of sewage filtration?

aleksandr82 [10.1K]

Answer:

Some general principles are given below in the explanation segment.

Explanation:

Sewage treatment seems to be a method to extract pollutants from untreated sewage, consisting primarily of domestic sewage including some solid wastes.

<u>The principles are given below:</u>

Unless the components throughout the flow stream become greater than the ports or even the gaps throughout the filter layer, those holes would be filled as either a result of economic detection.
The much more common element of filtration would be the use of gravity to extract a combination.
Broadcast interception or interference.
Inertial influence.
Sieving seems to be an excellent method to distinguish particulates.

8 0

3 years ago

A well-insulated, rigid tank has a volume of 1 m3and is initially evacuated. A valve is opened,and the surrounding air enters at

DiKsa [7]

Answer:

0.5 kW

Explanation:

The given parameters are;

Volume of tank = 1 m³

Pressure of air entering tank = 1 bar

Temperature of air = 27°C = 300.15 K

Temperature after heating = 477 °C = 750.15 K

V₂ = 1 m³

P₁V₁/T₁ = P₂V₂/T₂

P₁ = P₂

V₁ = T₁×V₂/T₂ = 300.15 * 1 /750.15 = 0.4 m³

$dQ = m \times c_p \times (T_2 -T_1)$

For ideal gas, $c_p$ = 5/2×R = 5/2*0.287 = 0.7175 kJ

PV = NKT

N = PV/(KT) = 100000×1/(750.15×1.38×10⁻²³)

N = 9.66×10²⁴

Number of moles of air = 9.66×10²⁴/(6.02×10²³) = 16.05 moles

The average mass of one mole of air = 28.8 g

Therefore, the total mass = 28.8*16.05 = 462.135 g = 0.46 kg

∴ dQ = 0.46*0.7175*(750.15 - 300.15) = 149.211 kJ

The power input required = The rate of heat transfer = 149.211/(60*5)

The power input required = 0.49737 kW ≈ 0.5 kW.

3 0

3 years ago

8. Question You should never drive: When weather conditions are not ideal. When road conditions are not ideal. Without having ma

LiRa [457]

The answer is All of the above

6 0

2 years ago

Which of the following are tips to help a speaker use their own voice?

djverab [1.8K]

D) All of the above.

4 0

3 years ago

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