In: Mechanical Engineering

choose the best answer:

A-
An ideal gas enters an adiabatic nozzle at 10 m/s and exits at 300
m/s. If the incoming specific enthalpy of the gas is 2,111 kJ/kg,
what is the exiting specific enthalpy of the gas in
kJ/kg?

Choices: 1: 2021.1 Kj/Kg , 2: 2200.9 kj/Kg , 3: 92011 Kj/Kg ,
-2021.2 kj/Kg.

B- A material with a specific heat, Cp, of 5 kJ/kg-K passes
through an insulated turbine at 4 kg/s. The incoming temperature of
the material is 100°C and the exiting temperature is 50°C.
Determine the shaft work in kW.

Choices: 1: 1000 KW , 2: -1000 KW , 3: 250 KW , 4: -250
KW.

C- Which of the following statements about a well-insulated
heat exchanger is false (ignoring kinetic and potential energy
changes):

Choices: 1: heat is exchanged between the system and the
surroundings , 2: the 2 materials do not physically mix , 3: energy
is exchanged between the materials , 4: the sum of the enthalpy
changes equals zero.

D- An open vat contains 1 kg of boiling ammonia at 1 bar.
Calculate the time (in seconds) it takes for the vat to empty if
the heat is added at a rate of 100 kW?

Answer: ?

As you mentioned in que that choose best option it means I have to answers only McQ type questions so I had solved first three McQ with explaination so please rate me thumbs up for the solution.

Air enters a nozzle steadily at 280 kPa and 77°C with a velocity
of 70 m/s and exits at 85 kPa and 320 m/s. The heat losses from the
nozzle to the surrounding medium at 20°C are estimated to be 3.2
kJ/kg.
The table for the ideal-gas properties of air is given
below.
Determine the exit temperature. (Round the final answer to one
decimal).
The exit temperature is ______K
Determine the total entropy change for this process. (Round the
final...

Prove that the adiabatic process of an ideal gas in a
simple compressible closed system is the polytropic process of n=k
( where k is the specific heat rate) by using the thermodynamic
first law.
Please answer quickly will rate positive thank u

Refrigerant 134a enters a well-insulated nozzle at 14 bar, 60°C,
with a
velocity of 37 m/s and exits at 1.2 bar with a velocity of 460 m/s.
For steady-state
operation, and neglecting potential energy effects, determine the
exit
temperature, in °C.

For
the ideal gas law to be most applicable, it is best for the gas to
exist at?

Argon gas enters an adiabatic compressor at 16.0 psia with 99 F
with a velocity of 49.9 ft/s. It exits at 225 psia and 209.5 ft/s.
If the isentropic efficiency of the compressor is 83.1%,
determine:
a) the exit temperature (R) of the argon
b) the work input to the compressor (Btu/lbm)

The pressure of a monatomic ideal gas doubles during an
adiabatic compression. What is the ratio of the final volume to the
initial volume (Vf/Vi)?

What is the difference between isothermal and adiabatic? 300 cm3
of an ideal diatomic gas at a pressure of 1 atmosphere and a
temperature of 300 K (i.e. room temperature) is contained by a
cylinder with a piston top. A camshaft turns and drives the piston
further into the cylinder, reducing the volume to 100 cm3 .
(a) What is the final pressure if this compression takes place
isothermally? What is the final pressure and temperature if the
compression takes...

N atoms of an ideal gas are contained in a cylinder with
insulating (adiabatic) walls, closed at one end by a piston.The
initial volume is Vi and the initial temperature is Ti. Find the
change in temperature, pressure and entropy that would occur if the
volume were suddenly increased to Vf by withdrawing the piston (Vf
> Vi).

N atoms of an ideal gas are contained in a cylinder with
insulating (adiabatic) walls, closed at one end by a piston.The
initial volume is Vi and the initial temperature is Ti . Find the
change in temperature, pressure and entropy that would occur if the
volume were suddenly increased to Vf by withdrawing the piston (Vf
> Vi).

A gas with cp = 0.950 kJ/kg-K enters an insulated nozzle at
30oC and a velocity of 8 m/s. The gas exits at a
velocity of 100 m/s. Assuming constant specific heats and ideal gas
behavior, what is the exit temperature of the gas?

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