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Engineering

Mario Monroe

Consider a large plane wall of thickness L = 0.4 m, thermal conductivity k = 2.3 W/m·K, and surface area A = 30 m2. The left side of the wall is maintained at a constant temperature of T1 = 90°C, while the right side loses heat by convection to the surrounding air at T[infinity] = 25°C with a heat transfer coefficient of h = 24 W/m2·K. Assuming constant thermal conductivity and no heat generation in the wall, (a) express the differential equation and the boundary conditions for steady one-dimensional heat conduction through the wall, (b) obtain a relation for the variation of temperature in the wall by solving the differential equation, and (c) evaluate the rate of heat transfer through the wall. Answer: (c) 9045 W

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Engineering

Guest

The practice of honoring those who have been lost in battle dates back to which two ancient

civilizations?

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Engineering

Hillary

What law What law directly affects your economic choices? directly affects your economic choices?

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Engineering

Peanut

A 7.5-ft-long solid steel shaft (G = 11.2 x 106 psi) is to transmit 15 hp at a speed of 1500 rpm. The shaft is limited to an allowable shearing stress of 4.5 ksi and an allowable angle of twist of 4 degrees.

Determine:

a. The power transmitted by the steel shaft in units of in-lb/sec.

b. The corresponding torque for the steel shaft in units of in-lb.

c. The required diameter of the shaft (Show all units in your calculations).

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Engineering

Hugh Weiss

You hang a heavy ball with a mass of 42 kg from a silver rod 2.7 m long by 1.9 mm by 2.6 mm. You measure the stretch of the rod, and find that the rod stretched 0.002902 m. Using these experimental data, what value of Young's modulus do you get

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Engineering

Ash

There is usually a positive side and a negative side to each new technological improvement?

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Engineering

Mia Fitzpatrick

Print person1's kids, call the incNumKids () method, and print again, outputting text as below. End each line with a newline. Sample output for below program with input 3:

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Engineering

Brodie Hancock

Prove that "a perfect conductor cannot contain an electrostatic field within it".

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Engineering

Aubrey Norton

True/False

An anemometer displays wind direction, wind speed, altitude and type of precipitation

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Engineering

Yurem Berger

Describe the basic types of chips produced in metal-cutting operations.

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Engineering

Warner

Calculate the surface temperature of a black surface, 1.6 m^2 in area if the rate of heat transfer is 632 kW. The Stefan-Boltzmann constant is σ = 5.67 x 10^-8 W/m^2 K^4 a) 1734 °C b) 273 °C c) 1625 K d) 1640 K e) 1682 K

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Engineering

Harley Neal

The portable lighting equipment for a mine is located 100 meters from its dc supply source. The mine lights use a total of 5 kW and operate at 120 V dc. Determine the required cross-sectional area of the copper wires used to connect the source to the mine lights if we require that the power lost in the copper wires be less than or equal to 5 percent of the power required by the mine lights.

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Engineering

Camilla Wagner

D 4.60 A designer requires a shunt regulator of approximately 20 V. Two kinds of zener diodes are available: 6.8-V devices with rz of 10 and 5.1-V devices with rz of 25. For the two major choices possible, find the load regulation. In this calculation neglect the effect of the regulator resistance R.

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Engineering

Serenity

Tech A says that one advantage of distributorless ignition systems is no moving parts to maintain. Tech B says that the

resistance of the coil primary winding can best be tested with a voltmeter. Who is correct?

Select one:

A. Tech A

B. Tech B

C. Both A and B

D. Neither Anor B

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Engineering

Snow White

Which statement is true of hydraulic tools? Hydraulic tools: a. Are powered by gasoline. b. Can cause electric shock. c. Use fire resistant fluid. d. Work like a loaded gun.

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