Ultimate Engineering Study Guide - Questions & Answers

A polymer rod is tested to determine its viscoelastic response. The rod's cross section is square with the side of 5mm. The rod's length before loading is 500mm. A tensile force of 500N is applied to the rod and the rod's length under load was measured as a function of time. Instantly after applying the load, the rod is stretched to 508mm. After 24 and 48 hour under load, the rod's length was measured as 550mm and 570mm, respectively. The load was then removed and the rod's length was measured as 525mm after a long time after the removal of the force (consider this as the permanent length). Determine the parameters of the Burger's model for describing this type of mechanical behavior
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Air is contained in a vertical piston-cylinder assembly by a piston with a mass of 15 kg and a face area of 0.01 m^2. The air has a mass of 5 g, and initially occupies a volume of 5 liters. The atmosphere exerts a pressure of 100 kPa on the top of the piston. Heat transfer of magnitude of 2.5 kJ occurs slowly from the air to the surroundings, and the volume of the air decreases to 2 liters. Neglecting friction between the piston and the cylinder wall, determine the change in specific internal energy of the air, in kJ/kg.
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The volume and the average density of an irregularly shaped body are to be determined by using a spring scale. The body weighs 7200 N in air and 4790 N in water. Determine the volume and the density of the body. State your assumptions.
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The turbine develops 150 kW of power, which is transmitted to the gears such that C receives 70% and D receives 30%. Determine the angle of twist of end E of the shaft relative to B . Express your answer using three significant figures.
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Consider a coaxial cable of inner radius a and outer radius b, filled with a lossless dielectric material. The phasor-domain fields inside of the cable (a < rho < b) for a time-harmonic wave traveling down the cable are given in cylindrical coordinates as: E= rho (1/ rho)e^- jkzH= (1/rho) 1/ or. e^-jkzCalculate the total time-average power (in Watts) flowing in the z direction down the cable.
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The major advantage CCDs have over other imaging techniques is that they Select one or more: a. have a higher quantum efficiency. b. have a linear response to light. c. yield output in digital format.
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g Explain how a differential pressure sensor is used to measure volume flow rate of a fluid through an orifice.
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A part made from hot-rolled AISI 1212 steel undergoes a 14 percent cold work operation. Determine the ultimate and yield strengths of a material after cold working. Determine the true strain of the material due to cold working. Also specify what happens to the material due to cold working?.
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As the reverse bias voltage across a PN junction is increased, the width of the depletion region will Select one: a. Increase b. Stays the same c. Decrease d. No way to determine e. None of these
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A combined cycle power plant has a net power output of 214 MW. Air enters the compressor of the Brayton cycle at 100 kPa and 37oC. The pressure ratio is 18, the turbine inlet temperature is 1620 K and the gases leaving the turbine are used to heat the steam of the Rankine cycle to 600oC and 6 MPa. The combustion gas leaves the heat exchanger (HRSG) at 420 K and the condenser pressure is 10 kPa. The isentropic efficiency of the compressor is 91%, the gas turbine isentropic efficiency is 93%, the steam turbine isentropic efficiency is 92% and the pump efficiency is 65%. The condenser sub-cools the water by 10oC (10oC less than the saturation temperature). Using variable specific heat analysis, determine:
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Mass When scientists make recommendations concerning environmental standards, the most important single measure is the mass of the pollutant that is present. If we have data on the number of particles per cubic centimeter for some particle of diameter p, then since we can compute the volume of each particle, knowing the mass density of the particle would enable us to compute the total mass of particulates. The actual density of particulate matter varies slightly with the different types of particles, but a typical density is about 1.5 g/cm3. Use this value for density in answering the questions below. 1. Write down an expression for the mass of a single particle of diameter p, measured in um. 2. Set up an integral that represents the total mass of particles per cubic centimeter found in the atmosphere above Pasadena. Estimate the value of this integral, and explain how you made the estimation. Is your estimate an over- or underestimate? 3. Write down an integral that represents the additional mass of particulate matter (per cm3) that would be removed from the air over Pasadena if the standard were changed from 10 um to 2.5 um. What standard would be required if we wanted to reduce the mass of the particulates by 10%?
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The Space Shuttle carried a reconnaissance satellite into a 173-nmi circular parking orbit. Now the satellite is to be placed into an elliptical orbit with perigee at 175 nmi and a period of 24 h. Required:a. Find the V required along with the characteristics of the new orbit. b. Find the V required for a Hohmann transfer from the surface of a nonrotating Earth to the parking orbit.
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The covers for multioutlet assemblies are available in steel, ____, and PVC with vinyl laminates of different colors and wood veneers such as maple, cherry, mahogany, and oak.
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Technician A says that freewheeling engines are not in danger of valve damage due to a broken timing component. Technician B says that balance shafts do not need to be timed to the crankshaft. Who is correct
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Tech A says that overcharging can lead to short life of bulbs and other electrical devices. Tech B says that the charging system regulated voltage is checked with maximum load on the battery. Who is correct
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Secondary recovery techniques a. include sealing fractures in the rock to concentrate oil in pockets called traps. b. usually enable drillers to get almost 100% of the oil out of the ground. c. are used to coax more oil out of a drilled hole. d. include the use of steam to make oil more viscous.
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A system is available for the ultrafiltration of protein solutions. On Monday, you filter a globular protein with 12,000 Da molecular weight, and it is fully retained. On Tuesday, you filter a 120,000 Da molecular weight globular protein at the same molar concentration and using the same membrane. The transmembrane flux was the same on both days. Assuming identical boundary layer thicknesses for both filtrations, in which case will the polarization modulus cw /cb be greater? What is the relationship between the polarization moduli for the two cases?
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Each piston has a radius of 45 mm and the cylinder has a wall thickness of 2 mm . Determine the maximum force P that can be exerted on each of the two pistons so that the circumferential stress in the cylinder does not exceed 5 MPa .
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Technician A says that engine performance is enhanced at upper rpm when cam timing is advanced. Technician B says that more valve overlap enhances lower engine rpm. Who is correct
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Tech A says to always check the chain, steel cable, or sling and bolts to make sure they are in good condition before using them with an engine hoist. Tech B says that to prepare an engine hoist for lifting an engine, you should get the hoist as far to one side of the engine as possible. Who is correct
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4- Consider a refrigerator that consumes 320 W of electric power when it is running. If the refrigerator runs only one quarter of the time and the unit cost of electricity is $0.13/kWh, the electricity cost of this refrigerator per month (30 days) is (a) $4.9 (b) $5.8 (c) $7.5 (d) $8.3 (e) $9.7
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ost residences with modern hydronic heating systems use ____________________ baseboard heat transfer for terminal heating units.
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Air is expanded isentropically from a reservoir in which the pressure is 1000 kPa to a pressure of 150 kPa. A normal shock occurs at this point in flow. Find the pressure downstream of the shock wave.
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Steam expands in a turbine from 6 MPa and 500 0C to 0.2 MPa and 150 0C at a rate of 1.2 kg/s. Heat is lost from the turbine at a rate of 34 kJ/s during the process. What is the power output of the turbine
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