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2 years ago

The iron-blade plow allowed humans to increase food production during what age?

Engineering

1 answer:

lilavasa [31]2 years ago

4 0

Answer:

The Iron Age

Explanation:

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What makes building an airplane while flying so difficult?

Naddik [55]

Answer: Because if something goes wrong while you are flying it it will crash

Explanation:

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2 years ago

8. The operation of a TXV is controlled by the

Katena32 [7]

Answer should be C hopefully

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2 years ago

A stainless steel ball (=8055 kg/m3, Cp= 480 J/kgK) of diameter D =15 cm is removed from theoven at a uniform temperature of 3

aleksandrvk [35]

Answer:

i) 25.04 W/m^2 .k

ii) 23.82 minutes = 1429.2 secs

Explanation:

Given data:

Diameter of steel ball = 15 cm

uniform temperature = 350°C

p = 8055 kg/m^3

Cp = 480 J/kg.k

surface temp of ball drops to 250°C

average surface temperature = ( 350 + 250 ) / 2 = 300°C

i) Determine the average convection heat transfer coefficient during the cooling process

Note : Obtain the properties of air at 1 atm at average film temp of 30°C from the table " properties of air " contained in your textbook

average convection heat transfer coefficient = 25.04 W/m^2 .k

ii) Determine how long this process has taken

Time taken by the process = 23.82 minutes = 1429.2 seconds

Δt = Qtotal / Qavg = 683232 / 477.92 = 1429.59 secs

attached below is the detailed solution of the given question

3 0

2 years ago

A world class runner can run long distances at a pace of 15 km/hour. That runner expends 800 kilocalories of energy per hour. a)

maks197457 [2]

Answer: a) 1.05kW b) 3.78MJ c) 5.3 bars

Explanation :

Conversions give 900 kcal as 900000 x 4.2 J/cal {4.2 J/cal is the standard factor}

= 3780kJ

And 1 hour = 3600s

Therefore, Power in watts = 3780/3600 = 1.05kW = 1050W

At 15km/hour a 15km run takes 1 hour.

1 hour is 3600s and the runner burns 1050 joule per second.

Energy used in 1 hour = 3600 x 1050 J/s

= 3780000 J or 3.78MJ

1 mile = 1.61km so 13.1 mile is 13.1 x 1.61 = 21.1km

15km needs 3.78 MJ of energy therefore 21.1km needs 3.78 x 21.1/15 = 5.32MJ =5320 kJ

Finally,

1 Milky Way = 240000 calories = 4.2 x 240000 J = 1008000J or 1008kJ

This means that the runner needs 5320/1008 = 5.3 bars

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3 years ago

What type of degree is needed to be an architect?

Rina8888 [55]

Architects must have a professional bachelor's or master's degree in architecture from a program that has been accredited by the National Architectural Accrediting Board, and a state license.

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2 years ago

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