Asimply supported 2024 aluminum beam is 3 ft long and loaded by 2 equal downward concentrated forces at the 1/3 points. the cross section is rectangular with a height of 4 inches and thickness of .5 inches. at the center of the beam a crack extends vertically 0.2" upwards from the bottom (all the way across the thickness). if the fracture toughness for this material is 20.9 ksi*in^(0.5), determine the magnitude of the applied forces necessary to cause the crack to extend

If you were designing a bumper for a car, would you prefer it to exhibit elastic or plastic deformation? why? consider the functions of a bumper in both a minor "fender-bender" and a major collision.

Ajournal bearing has a journal diameter of 3.250 in with a unilateral tolerance of 20.003 in. the bushing bore has a diameter of 3.256 in and a unilateral tolerance of 0.004 in. the bushing is 2.8 in long and supports a 700-lbf load. the journal speed is 900 rev/min. find the minimum oil film thickness and the maximum film pressure for both sae 20 and sae 20w-30 lubricants, for the tightest assembly if the operating film temperature is 160°f. a computer code is appropriate for solving this problem.

The filament of an incandescent lamp has a temperature of 2000k. calculate the fraction of radiation emitted in the visible light band if the filament is approximated as blackbody