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ivann1987 [24]
3 years ago
8

Circular fins are employed around the cylinder of a lawn mower engine to dissipate heat. The fins are made of aluminum are 0.3-m

thick, and extend 2 cm from base to tip. The outside diameter of the engine cylinder is 0.3 m. Design operating conditions are Tai 30°C and h-12 Wm2.K. The maximum allowable cylinder temperature is 300°C. Estimate the amount of heat transfer from a single fin. How many fins are required to cool a 3-kw engine operating at 30% thermal efficiency, if 50% of the total heat given off is transferred by the fins?

Engineering
1 answer:
frosja888 [35]3 years ago
8 0

Answer: heat through each fin is 291W

Total no of required fin from design calculations is 3

Explanation:

The detailed calculations and explanation is shown in the image below.

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You just purchased a 400-L rigid tank for a client who works in the gas industry. The tank is delivered pre-filled with 3 kg of
solniwko [45]

Answer:

the pressure reading when connected a pressure gauge is 543.44 kPa

Explanation:

Given data

tank volume (V) = 400 L i.e 0.4 m³

temperature (T) =  25°C  i.e. 25°C + 273 = 298 K

air mass (m)  = 3 kg

atmospheric pressure  = 98 kPa

To find out

pressure reading

Solution

we have find out pressure reading by gauge pressure

i.e. gauge pressure = absolute pressure - atmospheric pressure

first we find absolute pressure (p) by the ideal gas condition

i.e pV = mRT

p = mRT / V

p = ( 3 × 0.287 × 298 ) / 0.4

p = 641.44 kPa

so

gauge pressure = absolute pressure - atmospheric pressure

gauge pressure = 641.44 - 98

gauge pressure = 543.44 kPa

6 0
3 years ago
What is a business cycle? a period of economic growth followed by economic contraction the amount of time it takes a business to
Rzqust [24]

Business cycle and its growth followed by economic contraction the amount of time it takes a business to produce products in the following way.

Explanation:

The business cycle is the periodic but irregular up-and-down movement in economic activity, measured by fluctuations in real gross domestic product (GDP) and other macroeconomic variables.

A business cycle is typically characterized by four phases—recession, recovery, growth, and decline—that repeat themselves over time.

Economists note, however, that complete business cycles vary in length. The duration of business cycles can be anywhere from about two to twelve years, with most cycles averaging six years in length.

FACTORS THAT SHAPE BUSINESS CYCLES

Volatility of Investment Spending

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Momentum

Technological Innovations

Variations in Inventories

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7 0
3 years ago
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What causes the charging system warning lamp to go out when the engine starts up?
Flura [38]
B is the answer I believe so
7 0
3 years ago
When you first start a car after it has been sitting for more than an hour, it pollutes up to ......times more than when the eng
lesya [120]
20 time more then when it’s warm
6 0
4 years ago
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A 20-mm-diameter steel bar is to be used as a torsion spring. If the torsional stress in the bar is not to exceed 110 MPa when o
ch4aika [34]

Answer:

1.887 m

Explanation:

(15 *pi)/180

= 0.2618 rad

Polar moment

= Pi*d⁴/32

= (22/7*20⁴)/32

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Torque on shaft

= ((22/7)*20³*110)/16

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L = Gjθ/T

= 79.3x10⁹x(1.571*10^-8)x0.2618/172.8

= 1.887 m

The length of the bar is therefore 1.887 meters

5 0
3 years ago
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