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VikaD [51]
3 years ago
14

What is compression ratio of an Otto cycle? How does it affect the thermal efficiency of the cycle?

Engineering
1 answer:
GuDViN [60]3 years ago
6 0

Answer:

r= \dfrac{V_1}{V_2}

\eta =1-\dfrac{1}{r^{\gamma-1}}

Explanation:

Compression ratio:

   Compression ratio is the ratio of volume in the cylinder.Generally it is denoted by r.

The compression ratio for Otto cycle is about 8 to 12.But the compression ratio of diesel engine is about 14 to 25.

So from the Otto cycle compression ratio can be define as

r= \dfrac{V_1}{V_2}

As we know that efficiency defines as the ratio of work out to the heat input.In the Otto cycle the efficiency is given as in terms of compression ratio r as

\eta =1-\dfrac{1}{r^{\gamma-1}}

Where γ is the heat capacity ratio.

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potential difference is the work done in moving a unit positive charge from one point to another in an electric field. State Tru
kow [346]

Answer:

True

Explanation:

Because the <u>Electric Magnetic Field</u> is the work done per unit charge where other forms of energy is tranferred to electrical energy

5 0
4 years ago
You have a piece of 1045 steel 80 cm long and 30 cm wide and 15cm high. In this piece it is desired to make a groove along the 8
tino4ka555 [31]

Answer:

0.65 m/min

Explanation:

The volume of material to be removed is

80*8*10 = 650 cm^3

The tool has a diameter of 4 mm and a maximum axial cutting capacity of 50 mm, so its cross section normal to advance is

0.4*5 = 2 cm^2

If the groove have to be made in T = 5 minutes the advance speed would be

V/(S * T)

650/(2 * 5) = 65 cm/min = 0.65 m/min

4 0
3 years ago
Explain three (3) modes of heat transfer in air conditioning system.
LenKa [72]

Answer:

1. Conduction

2. Convection

3. Radiation

Explanation:

The 3 modes of heat transfer i an air conditioning system:

1. Conduction:

The transfer of heat by conduction  takes place in solid and is when the conduction takes place as a result of direct contact in between the interacting material which transfer the heat energy from particle to particle thus conducting the heat through out the system.

2. Convection:

The other mode for the transfer of heat which takes place especially in fluids - gases and liquids is through the technique of convection in which the transfer of heat takes place by the circular motion of the atoms and molecules of the fluid which carries the heat energy and results in the distribution of the heated fluid in the entire system thus transferring all the heat energy in the entire system.

3. Radiation:

The third mode of heat transfer in the air conditioning system is through radiation. This method transfers the heat by making use of the electro-magnetic radiation in the infra red spectrum where the waves of the spectrum transfers the heat energy with the help of a medium or without any medium at all.

Thus making the radiation method of heat transfer as the only method out of the three methods which does not require the material medium for the transfer of heat energy.

4 0
3 years ago
How much does it cost to repair a broken train? (Fill in the blanks)
Lana71 [14]
900,000 dollors muny
8 0
2 years ago
A carpenter uses a hammer to strike a nail. Approximate the hammer's weight of 1.8lbs, as being concentrated at the head, and as
bija089 [108]

Answer:

The average force F exherted by the nail over the hammer is 178.4 lbf.

Explanation:

The force F exherted by the nail over the hammer is defined as:

F = |I|/Δt

Where I and Δt are the magnitude of the impact and the period of time respectively. We know that the impact can be calculated as the difference in momentum:

I = ΔP = Pf - Pi

Where Pf and Pi are the momentum after and before the impact. Recalling for the definition for momentum:

P = m.v  

Where m and v are the mass and the velocity of the body respectively. Notice that final hummer's momentum is zero due to the hammers de-acelerate to zero velocity. Then the momentum variation will be expressed as:

ΔP =  - Pi = -m.vi

The initial velocity is given as 50 mph and we will expressed in ft/s:

vi = 50 mph * 1.47 ft/s/mph = 73.3 ft/s

By multiplyng by the mass of 1.8 lbs, we obtain the impulse I:

|I|= |ΔP|= |-m.vi| = 1.8 lb  * 73.3 ft/s = 132 lb.ft/s

Dividing the impulse by a duration of 0.023 seconds, we finally find the force F:

F =  132 lb.ft/s / 0.023 s = 5740 lb.ft/s^2  

Expressing in lbf:

F = 5740 lb.ft/s^2 * 0.031 lbf/lb.ft/s^2  =  178.4 lbf

7 0
4 years ago
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