When a rear wheel drive car accelerates around a bend at high speeds, the drive shaft is subject to both bending and torsional loads. the accelerating torque is reasonably constant at 400 nm while the bending moment at a critical section varies due to cornering and can be expressed in n-m as m = 250 + 800sinωt. design the shaft for infinite life using de-goodman criterion assuming the shaft is uniform cross-section. the reliability in estimating the endurance limit should be at least 99% and a safety factor of 4.5 should be used in the design. the shaft is forged from 1080 steel of ultimate strength 620 mpa and yield strength 380 mpa.

When using the ohmmeter function of a digital multimeter, the leads are placed in what position relative to the component being tested? a. parallel b. control c. series d. line

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

For the closed feedwater heater below, feedwater enters state 3 at a pressure of 2000 psia and temperature of 420 °f at a rate of ix10 ibhr. the feedwat extracted steam enters state 1 at a pressure of 1000 psia and enthalpy of 1500 btu/lbm. the extracted er leaves at an enthalpy of 528.7 btu/lbm steam leaves as a saturated liquid. (16) a) determine the mass flow rate of the extraction steam used to heat the feedwater (10) b) determine the terminal temperature difference of the closed feedwater heater