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Engineering

Lucia York

An exercise room has six weight-lifting machines that have no motors and seven treadmills, each equipped with a 2.5-hp (shaft output) motor. The motors operate at an average load factor of 0.7, at which their efficiency is 0.77. During peak evening hours, all 13 pieces of exercising equipment are used continuously, and there are also two people doing light exercises while waiting in line for one piece of the equipment. Assuming the average rate of heat dissipation from people in an exercise room is 740 W, determine the rate of heat gain of the exercise room from people and the equipment at peak load conditions.

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Engineering

Cynthia

How do you define a renewable energy source? Why are coal, oil, and natural gas not renewable energy sources?

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Engineering

Emely Pratt

Which of the following properties or characteristics do not apply to metals (two correct answers) : (a) good thermal conductivity, (b) high strength, (c) high electrical resistivity, (d) high stiffness, and (e) ionic bonding?

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Engineering

Jaydin Stevens

You are asked to look into adding a circuit for a new pump in a hydraulics lab. After some investigation of the electrical service in the building you find that there are a few voltage options; 120V, single-phase; 208V, single-phase; 208V, 3-phase. Which pump electrical choice would be the most economical in terms of first cost for electrical construction materials and overall electrical efficiency

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Engineering

Dalia Avery

What is the range of a 32-bit signed integer?

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Engineering

Melanie Mooney

A 25 kg iron block initially at 280°C is quenched in an insulated tank that contains 100 kg of water at 18°C. Assuming the water that vaporizes during the process condenses back in the tank, determine the total entropy change during this process.

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Engineering

Kody Maynard

What are the purposes of the various types of drawings used for the design and erection of steel framed buildings?

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Engineering

Carolina Robles

What is engine knock? What cause the engine knock problem?

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Engineering

Marble

A room contains 50 kg of dry air and 06 kg of water vapor at 25°C and 95 kPa total pressure. The saturation p ressure of water at 25 "C is 3.1698 kPa. The molar masses for air and water are 29 kg/kmol and 18 kg/kmol, respectively Determine (a) The specific humidity of air in the room; (b) The relative humidity of air in the room.

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Engineering

Darnell Tanner

How does a wooden whistle make sound?

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Engineering

Moyer

Thirty-six grams of air in a piston-cylinder assembly undergo a Stirling cycle with a compression ratio of 7.5. At the beginning of the isothermal compression, the pressure and volume are 1 bar and 0.03 m3, respectively. The temperature during the isothermal expansion is 1200 K. Assuming the ideal gas model and ignoring kinetic and potential energy effects, determine the net work, in kJ.

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Engineering

Guest

True or false

1. The detonation of a low explosive produces a pressure wave that travels at less than 340 m/s. Obj. 5.2

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Engineering

Carmen Mayer

Liquid benzene and liquid n-hexane are blended to form a stream flowing at a rate of 1700 lbm/h. An on-line densitometer (an instrument used to determine density) indicates that the stream has a density of 0.810 g/mL. Using specific tractors from Table B. 1, estimate the mass and volumetric feed rates of the two hydrocarbons to the mixing vessel (in U. S. customary units). State at least two assumptions required to obtain the estimate from the recommended date.

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Engineering

Villa

Flow at the inlet and outlets can be assumed One-dimensional for the sake of simplicity. (a) Explain how this assumption simplifies the Reynolds Transport Theorem equation (provide complete, detailed answer) (b) This assumption introduces errors into the calculations, as it assumes flow properties do not vary across the inlet/outlet area. How this error changes with the area (does it increase or decrease) ?

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Engineering

Guest

Estimate the theoretical fracture strength (in MPa) of a brittle material if it is known that fracture occurs by the propagation of an elliptically shaped internal crack of length 0.25 mm that has a tip radius of curvature of 0.006 mm when a stress of 1060 MPa is applied. Group of answer choices (A) 16,760 MPa

(B) 8,380 MPa

(C) 132,500 MPa

(D) 364 MPa

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