Question #14:

An engine using 1 mol of an ideal gas initially at 18.5 L and 402 K performs a cycle
consisting of four steps:

1) an isothermal expansion at 402 K from 18.5 L to 41.2 L
2) cooling at constant volume to 273 K
3) an isothermal compression to its original volume of 18.5 L
4) heating at constant volume to its original temperature of 402 K

Find its efficiency. Assume that the heat capacity is 21 J/K and the universal gas constant is 0.08206 L · atm/mol/K = 8.314 J/mol/K.

Answers

Answer 1

The efficiency of the engine through the four steps cycle is 83.4%.

What is the efficiency of a machine?

The efficiency of a machine is the ratio of useful work done by the machine and the work done on the machine expressed as a percentage.

The efficiency of the engine is given by:

[tex]ɛ=\frac {W} {Q}[/tex]

where;

W is the work done in the four steps,Q is the energy input

Since there at four steps in a cycle:

[tex]ɛ=\frac {W_1+ W_2+W_3+W_4} {Q_1+Q_2+Q_3+Q_4}[/tex]

The work done in the first step (isothermal expansion) is given by:

[tex]W_1=nRT_1\ln{\frac {V_2} { V_1}}[/tex]

where:

n= 1 mole, T1 = 402 K, V2 = 41.2 L, V1 = 18.5 L

Substituting the values:

[tex]W_1 = 1 × 8.314 × 402 \times ln{\frac {41.2} {18.5}} = 2676.01 J \\ [/tex]

Steps 2 and 4 are constant volume processes, therefore;

[tex]W_2=W_4=0[/tex]

The work done in the third step (isothermal expansion) is given by:

[tex]W_3=nRT_3\ln{\frac {V_4} { V_3}} [/tex]

where;

n = 1 mol, T3 = 273 K, V4 = 41.2 L, V3 = 18.5 L

Substituting the values:

[tex]W_3 = 1 × 8.314 × 273 \times ln{\frac {41.2} {18.5}} = 1817.29 J \\ [/tex]

[tex]W_3 = 1 × 8.314 × 273 \times ln{\frac {41.2} {18.5}} = 1817.29 J \\ [/tex]Heat enters the system only during steps (1) and (4).

The internal energy of the gas increases in step 4 but no work is done, while the internal energy is constant change in step 1 but work is done by the gas.

Thus;

[tex]Q_2=Q_3=0[/tex]

The heat that enters the system during the isothermal expansion is given by:

[tex]Q_1=W_1[/tex]

The heat that enters the system on step 4 at constant volume is given by:

[tex]Q_4=C_V(T_4-T_3)[/tex]

where:

Cv =21 J/K, T3 = 273 K, T4 = 402 K

Substituting the values:

[tex]Q_4= 21 × (402 - 273) = 2709 \: J[/tex]

Solving for efficiency, ɛ:

[tex]ɛ=\frac {2676.01+ 0+0+1817.29} {2676.01+0+0+2709} = 83.4\%[/tex]

Therefore, the efficiency of the engine is 83.4%.

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Related Questions

Question 4

20 pts

A student connects a length of unknown

material in series with a battery and an

ammeter (which measures current flow).

When the circuit is complete, the ammeter

reads that no current is flowing.

The unknown material is most likely –

Insulator

Semiconductor

Superconductor

Conductor

Answers

If current did not flow in the circuit, it simply implies that the material is an insulator.

What is an insulator?

An insulator is a material that does not conduct electricity. A circuit is a  path  that is provided for the flow of current.

If this material was connected into a complete circuit yet current did not flow in the circuit, it simply implies that the material is an insulator.

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An astronaut floating alone in outer space throws a baseball. If the ball moves away at 20 m/s, the astronaut will:.

Answers

Answer:

Move the opposite direction ( at a lesser magnitude of velocity)

Explanation:

The main difference between a radio wave and a light wave is its:.

Answers

Answer:

Speed.

Their speeds are different; Have you ever heard the metaphor the speed of light? For this case, we must turn that into a reality. So, people refer to light speed as the fastest travelling thing in the world, and that is right, unless there is a thing faster than light that was never classified. Unlikely the case. The speed of sound through air travels a lot slower than light. Look at the diagrams below to see what I mean by that.

                                                             • • •

As shown in the diagrams, sound speed is WAY slower than light speed!

Magnetism is due to the movement of ______.

Answers

Answer:

electrons

Explanation:

Brainliest

[tex]\qquad\qquad\huge\underline{{\sf Answer}}♨[/tex]

Magnetism is due to the movement of charge

Both magnetic fields are caused due to attraction and repulsion of charges, where electric fields is caused by stationary charges, while magnetic fields are caused by moving charges

A step-up transformer increases the voltage 20 timesIf the voltage of the primary coil is 100V_{i} what is the voltage of the secondary coll? Answer only a number without units or commas

Answers

Answer:

2000

Explanation:

well it is just   20 * 100 = 2000 v

You are taking measurements of sound waves. Every ¼ second, the sound waves pass your detector. What is the wave’s frequency and what is the wave’s period? (Use correct units)

Answers

Answer:

hope this helps, you can ask any questions for clarification

How much work do you do on a 25- kg backpack when you walk a horizontal distance of 100m ?

Answers

Answer:

2,500

Explanation:

There are ___ particles that make up an atom which are the smallest unit of an ___.

Answers

Answer:

subatomic, element

Explanation:

Subatomic particles are protons, neutrons, and electrons. Atoms are the smallest unit of an element.

please answer this small qustion of what happens whan oil is in the ochen

Answers

Answer:

When oil is spilled in the sea it will normally break up and be dissipated or scattered into the marine environment over time. This dissipation is a result of a number of chemical and physical processes that change the compounds that make up oil when it is spilled. The processes are collectively known as weathering.

Hope This It What You Wanted :)

What is simple harmonic oscillation? express your answer verbally, mathematically, and visually.

Answers

Simple harmonic motion is the motion in objects where the restoring for d is directly proportional to the body displacement.

What is simple harmonic motion?

Simple harmonic motion a type of periodic motion where the force that restores moving object to it's right position is directly proportional to the magnitude of body's displacement and this normally acts towards the object's equilibrium position.

The formulate for simple harmonic motion are

,F = −kx, where F is the force, x is the displacement, and k is a constanst. An example of a simple harmonic oscillator is the vibration of a mass attached to a vertical spring.

Simple harmonic oscillator can be represented by the equation x ( t ) = A cos ⁡ ( 2 π f t ) x(t) = A\cos(2\pi f t) x(t)=Acos(2πft)x,

where t is period.

x is displacement

A is amplitude.

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How do you boost the amount of electricity a fuel cell system produces?.

Answers

For this one it should be A single fuel cell generates approximately one volt of electricity. Individual fuel cells are combined to form a fuel cell stack to enhance the amount of electricity produced.

The amount of electricity a fuel cell system produces is boost by combined to form a fuel cell that is battery.

What is battery?

A battery is a device that uses an electrochemical oxidation-reduction (redox) cycle to turn the chemical energy included in its active components directly into electric energy. An electric circuit is used in this kind of reaction to transmit electrons from one substance to another.

The actual elector-chemical unit used to produce or store electric

For this one it should be A single fuel cell generates approximately one volt of electricity. Individual fuel cells are combined to form a fuel cell stack to enhance the amount of electricity produced.

The amount of electricity a fuel cell system produces is boost by combined to form a fuel cell that is battery.

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Systems in the body interact to carry out life functions. The muscles of the body are part of the musculoskeletal system. Which system provides the impulses that cause the muscles to contract?
A.
circulatory
B.
integumentary
C.
respiratory
D.
nervous

Answers

D. nervous system!! hope this helps!!

Which of the following is an example if harmonic motion?

Answers

Answer:

"A pendulum swinging back and forth" is an example of harmonic motion

X = Xo cos ω t

Explains the back and forth motion of the pendulum

7. A rocket has a weight of 30,000 N on earth. a) What is the mass of the rocket in outer space? Use appropriate calculations and arguments to support your answer.
b) Calculate the weight of the rocket on planet X (g=7.5 N/Kg)
c) What is the weight of the rocket in outer space? Provide reasons to support your answer

Answers

Explanation:

a) mass=3000kg

b) weight on planet x=3000 × 7.5

=22,500N

c) Weight in outer space will be equal to zero

since the gravity in outer space is negligible

I. Briefly answer the following questions.
1. Do renewable energy sources have little or no impact compared to
non- renewable resources? Why?

2. Discuss two human activities that endanger renewable resources.​

Answers

Most sources of renewable energy result in little to no emissions, even when considering the full life cycle of the technologies. Renewable energy emits no or low air pollutants.Because renewable energies are not burned like fossil fuels, they do not release pollutants into the atmosphere and provide a cleaner, healthier environment. Sources of renewable energy are found everywhere in the world and cannot be depletedSome human activities that endanger renewable resources are the hunting and fishing of animals for food, and the clearing of forests for urbanization and wood use.

Do you think there could be another period of time when so many brilliant discoveries are made in such a span of time? Why or Why not?

Answers

There won't be another period where many brilliant discoveries are made in such a span of time because of the high degree of advancement already.

What is Technology?

Tgis is defined as the application of scientific knowledge for practical purposes.

We have advanced technological advancement which is why there won't be many discoveries in such time span.

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A force of 20 N is applied tangentially to a wheel of mass 10 kg and diameter 5 m. Calculate the torque applied and angular velocity at the end of 10 second?​

Answers

Answer:

N = 20

10 + 10 + -5 = 20

N + -5 = 10 -5 + 20

Therefore , the answer is N=20

Explanation:

#BrainliestBunch

An inductor produces a back emf in a dc series rl circuit when a switch connecting the battery to the circuit is closed. We can explain this by.

Answers

Hi there!

Let's say that a series RL circuit is constructed, with the switch left open.

When the switch is closed, a current will start flowing in the circuit. The INCREASING current will go through the loops of the inductor, producing an INCREASING magnetic field and consequentially a magnetic flux through the inductor. (Use hand rules).

However, the inductor does NOT want to experience this increasing magnetic flux, so an emf in the OPPOSITE direction of the current will be produced to counteract the increasing flux. (The flux would also be in the opposite direction).

This is expressed with the equation:


[tex]\epsilon = -L \frac{di}{dt}[/tex]

ε = Back emf (V)
L = Inductance (H)

i = Current (A)
t = time (s)

With the negative sign, we can see that if the current of the circuit is INCREASING, the emf produced would be in the opposite direction.

A sample of helium behaves as an ideal gas as it is heated at constant pressure from 273 K to 388 K. If 80 J of work is done by the gas during this process, what is the mass of the helium sample? The universal gas constant is 8.31451 J/mol · K. Answer in units of g

Answers

The mass of the helium gas sample after the work is done by the gas during the process is 0.099 g.

Number of moles of the helium gas

The number of moles of the helium gas is calculated as follows;

W = nRT

where;

n is the number of molesW is the work doneR is universal gas constant = 8.31451 J/mol · KT is the final temperature = 388 K

273 K = 0⁰C and 388 K = 115⁰ C

from 0⁰C to 115⁰C = 115 - 0 = 115⁰ C

115⁰ C = 388 K

The number of moles is calculated as follows;

n = W/RT

[tex]n = \frac{80}{8.315 \times 388} \\\\n = 0.0248 \ mol[/tex].

Mass of the helium sample

Mass of the helium sample is calculated as follows;

m = Mn

where;

M is the molar mass of helium gas = 4 g/mol

m = 4 g/mol x 0.0248 mol

m = 0.099 g

Thus, the mass of the helium gas sample after the work is done by the gas during the process is 0.099 g.

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You push a 25.0kg wooden box across a wooden floor at a constant speed of 1.0m/s . the coefficient of kinetic friction is 0.20 . how large is the force that you exert on the box?

Answers

For  a 25.0kg wooden box across a wooden floor at a constant speed of 1.0m/s, The force is mathematically given as

F=49N

What is the force that you exert on the box?

Generally, the equation for the Force   is mathematically given as

F=uN

Therefore

F=25*9.8*0.20

F=49N

In conclusion, the force is

F=49N

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Which is a situation where two hockey pucks could have equal but opposite momentums? Assume that the ice is a frictionless surface.

A. if the hockey pucks weigh the same.

B. if the hockey pucks exert the same force on each other in the same direction while traveling at the same speed.

C. if the hockey pucks are traveling at the same speed, bounce off each other, and move in the opposite direction.

D. if the hockey pucks have the same mass.

Answers

As momentum is mass * velocity,
it has to be C, assuming their masses are the same. As the momentum would be equally distributed as momentum must be conserved( because none is lost to friction on the ice).

For pea plants, T represents a dominant allele for tall pea plants and t is the recessive allele for short pea plants. If two plants with the Tt genotype are crossed, what is the probability that offspring will exhibit the dominant trait?

Answers

Answer:

75%(TT,Tt,tt) Hope that helps

o
0
H
H
H
H
H
H
H
H
o
H
CI
icle
H
TIGER
1. What is the name of the process taking place in the diagram? Describe the process.
sents a
у
2. What is an ion?
Charged particle that has greater or fewer electrons than protons.
3. What is the solute in the diagram? Is the solute an electrolyte or a nonelectrolyte?
am
of three...
4. Will the solution conduct electricity? Explain.

Answers

Answer:

1) Ionization takes place as the Hydrochloric acid, a strong acid, ionizes completely in water to form the hydronium and chlorine (Cl−) ions

3) Water -- non electrolyte

4) it can conduct electricity because it forms ions

I hope my answer helps you.

A monochromatic light passes through a narrow slit and forms a diffraction pattern on a screen behind the slit. As the slit width increases, the diffraction pattern:.

Answers

As the slit width increases, the diffraction pattern gets narrower and vice versa.

Relationship between width and diffraction pattern

The increase in silt width leads to the narrowing of diffraction pattern of the  light because the increase of width reduces the space for the passing of light wave.

So we can conclude that as the slit width increases, the diffraction pattern gets narrower and vice versa.

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Question 3 of 20
A crate falling from a plane is part of a closed system that has 24450 J of
mechanical energy. If the kinetic energy of the crate increases from 10,000 J
to 15,000 J, what happens to the gravitational potential energy of the system?
A. It decreases from 15,000 J to
10,000 J.
B. It increases from 9450 J to
14,450 J.
C. It decreases from 14,450 J to
9,450 J.
O D. It increases from 10,000 J to
15,000 J.

Answers

Old potential energy:-

PE+KE=MEPE=ME-KEPE=24450-10000PE=14450J

New potential energy

PE=24450-15000PE=9450J

Option B is correct

How did the development of electrical signals sent through wires change communication?

A. The electrical signals were more accurate than optical semaphore signals.

B. Signals were amplified with distance.

C. Signals could be sent anywhere a wire could reach and no longer were restricted to line of sight.

D. Signals no longer attenuated with distance.

Answers

A

Explanation:

The electrical signals were more accurate than optical semaphore signals.

The development of electrical signals sent through wires change communication as signals could be sent anywhere a wire could reach and no longer were restricted to line of sight.

What is wire communication?

Wired communication refers to the transmission of data over a wire-based communication technology.

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Superkid, finally fed up with Superbully's obnoxious behaviour, hurls a 1.35 kg stone at him at 0.501 of the speed of light. How much kinetic energy do Superkid's super arm muscles give the stone

Answers

Answer:

See below

Explanation:

A lot !

KE = 1/2 m v^2

    = 1/2 * 1.35 * ( .501 * 3 * 10^8)^2 =

    1.5248 x 10^16 j

kinetic energy do Superkid's super arm muscles give the stone is 62.6 × 10⁶ J.

What is kinetic energy ?

Kinetic energy is the energy associated with a motion of a body. When a body is in motion having mass m then it has kinetic energy. Kinetic energy is denoted by K or T. it is expressed in joules. Kinetic energy is given by,

K = 1/2 mv²

Hence an object having zero mass or zero velocity have zero kinetic energy.

In this problem the stone is moving with velocity which is comparable with the speed of light, hence we have to find relativistic kinetic energy.

The relativistic kinetic energy is given by,

[tex]K = m_{0} c^2(\frac{1}{\sqrt{1-\frac{v^2}{c^2}} } -1)[/tex]

putting all the values in the equation

[tex]K = 1.35*3*10^8(\frac{1}{\sqrt{1-\frac{(0.5c)^2}{c^2} } }-1 )[/tex]

K = 62.6 × 10⁶ J

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if a Bob at rest explodes into two pieces? explain​

Answers

Answer:

the pieces must travel in opposite directions.

Explanation:

If a bomb at rest explodes into two pieces, the pieces must travel in opposite directions. Explain A bomb at rest explodes into two pieces. Let the mass of bomb be M and mass of two pieces be m1 respectively. Now, according to conservation of momentum: are velocities of two masses after explosion.

Which condition is necessary for a lunar eclipse to occur?.

Answers

For a lunar eclipse to occur, the Sun, Earth, and Moon must be roughly aligned in a line. Otherwise, the Earth cannot cast a shadow on the Moon's surface and an eclipse cannot take place. When the Sun, Earth, and Moon come together in a straight line, a total lunar eclipse takes

Answer 1-10 for branly all steps

Answers

The acceleration, a of the bodies given is the change in velocity with time and is given as follows:

a = 1.2 m/sa = 25 km/hra = 35.3 cm/mina = 7.125 km/mina = 1.69 m/sa = 108.1 m/hra = -1.0 cm/sa = 7.89 km/hra = 1.17 ft/sa = 3.13 km/hr

What is acceleration?

Acceleration is the rate of changeof velocity of an object with time.

Acceleration, a = change in velocity/time taken

For the given questions, the acceleration are as follow:

a = (40 - 10)/25 = 1.2 m/sa = (75 - 30)/1.8 = 25 km/hra = (90 - 60)/0.85 = 35.3 cm/mina = (77 - 20)/8 = 7.125 km/mina = (37 - 15)/13 = 1.69 m/sa = (40 - 0)/0.37 = 108.1 m/hra = (13 - 25)/12 = -1.0 cm/sa = (48 - 18)/3.8 = 7.89 km/hra = (52 - 38)/12 = 1.17 ft/sa = (43 - 17)/8.3 = 3.13 km/hr

Therefore, the acceleration of a body is either positive or negative.

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