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4 years ago

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A gasoline engine takes in air at 290 K, 90 kPa and then compresses it. The combustion adds 1000 kJ/kg to the air after which th

e temperature is 2050 K.
Using a cold air-standard analysis, i.e., constant specific heats at 300 K, find the compression ratio, compression specific work, and the highest pressure in the cycle. Repeat your analysis assuming temperature-dependent specific heats and comment on your results.

1 answer:

Inessa [10]4 years ago

4 0

Answer:

attached below

Explanation:

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2 Describe the four major disciplines of engineering and identify problems or projects that an engineer in each discipline might

Harman [31]

Answer: Starting of with Chemical Engineering something that they may encounter is a lack of adeptness man puissance. People that are working there are not much adept or having cognizance regarding to chemical industry. Something someone with a Civil engineering might encounter is the quandary of sustainable construction, and amendment construction site safety. To go on , something that Electrical engineering might encounter is a Non technical , Virtually an electrical engineer has to deal with an astronomical range of machines , control panels,instruments. For example you are working with circuit breakers,as anon as you’ll have expertise on any particular type of circuit breaker, there's a transmutation in trend and the CB you are working with is already obsolete. And last but no least , Something someone might encounter while doing Mechanical engineering is there toxic substances because their work environment is susceptible to fires, explosions, structural failures and equipment malfunctions.

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3 years ago

If copper (which has a melting point of 1085°C) homogeneously nucleates at 849°C, calculate the critical radius given values of

____ [38]

Answer:

The critical radius is -1.30 nm

Explanation:

Temperature for homogenous nucleation of copper, $T_{H} = 849^{0} C = 849 + 273 = 1122 K$

Melting point of copper, $T_{cu} = 1085^{0} C = 1085 + 273 = 1358 K$

Latent heat of fusion, $H_{f} = -1.77 * 10^{9} J/m^{3}$

Surface free energy, $\gamma = 0.200 J/m^{2}$

Critical radius, r = ?

The formula for the critical radius is given by:

$r = \frac{2 \gamma T_{cu} }{H_{f}(T_{cu} - T_{H}) }$

$r = \frac{2 * 0.2*1358 }{(-1.77 * 10^{9}) (1358 - 1122) }$

$r = \frac{543.2 }{(-1.77 * 10^{9}) 236}\\r = -1.30 * 10^{-9} m\\r = -1.30 nm$

The critical radius is -1.30 nm

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4 years ago

An automobile having a mass of 1100 kg initially moves along a level highway at 120 km/h relative to the highway. It then climbs

soldier1979 [14.2K]

Answer:

$-6111.11\ \text{kJ}$

$863.28\ \text{kJ}$

Explanation:

m = Mass of automobile = 1100 kg

v = Velocity of car = 120 km/h = $\dfrac{120}{3.6}\ \text{m/s}$

h = Height of hill = 80 m

g = Acceleration due to gravity = $9.81\ \text{m/s}^2$

Change in kinetic energy

$KE=\dfrac{1}{2}m(u^2-v^2)\\\Rightarrow KE=\dfrac{1}{2}\times 1100\times (0-(\dfrac{120}{3.6})^2)\\\Rightarrow KE=-611111.11\ \text{J}$

Change in kinetic energy is $-6111.11\ \text{kJ}$

Change in potential energy is given by

$PE=mgh\\\Rightarrow PE=1100\times 9.81\times 80\\\Rightarrow PE=863280\ \text{J}$

The change in potential energy is $863.28\ \text{kJ}$ .

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3 years ago

Liquid flows at steady state at a rate of 2 lb/s through a pump, which operates to raise the elevation of the liquid 100 ft from

Greeley [361]

Answer:

D) 1.04 Btu/s from the liquid to the surroundings.

Explanation:

Given that:

flow rate (m) = 2 lb/s

liquid specific enthalpy at the inlet ( $h_{1}=40.09$ Btu/lb)

liquid specific enthalpy at the exit ( $h_{2}=40.94$ Btu/lb)

initial elevation ( $z_1=0ft$ )

final elevation ( $z_2=100ft$ )

acceleration due to gravity (g) = 32.174 ft/s²

$W_{cv}$ = 3 Btu/s

The energy balance equation is given as:

$Q_{cv}-W{cv}+m[(h_1-h_2)+(\frac{V_1^2-V_2^2}{2})+g(z_1-z_2)]=0$

Since kinetic energy effects are negligible, the equation becomes:

$Q_{cv}-W{cv}+m[(h_1-h_2)+g(z_1-z_2)]=0$

Substituting values:

$Q_{cv}-(-3)+2[(40.09-40.94)+\frac{32.174(0-100)}{778*32.174} ]=0\\Q_{cv}+3+2[-0.85-0.1285 ]=0\\Q_{cv}+3+2(-0.9785)=0\\Q_{cv}+3-1.957=0\\Q_{cv}+1.04=0\\Q_{cv}=-1.04\\$

The heat transfer rate is 1.04 Btu/s from the liquid to the surroundings.

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3 years ago

Que os vizinhos diziam sempre aq lenhador? Responda com elementos do texto.

Alecsey [184]

Answer:

shsisdnd ajwdhdjeo sisksdne suspended wowodndjd

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3 years ago