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FirstExam(F09)_Soln - T he HashemiteU niversity Facultyof...

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The Hashemite University Faculty of Engineering Me chanic al Engine ering Departme nl Machine Design I Fall 2009 Instructor: Dr. Ala Hijazi First Exam Part I-Closed Book Please Read Questions Carefully - GoodLuck! (12 pointsl l. For the flowing statements circle the conect answer. Ceramics arebrittle andmuch stronger in compression than in tension. Thermoset polymers canbe melted andreformed. The factor of safety is dbfined as the ratio of strength to stress. If30 parts fail out ofeach100 parts, this means that the reliability is 0.3. Coldworking increases the ductility ofthe material. For a rotating ring, the maximum stress occurs at the outer surface. In a thick-walled pressure vessel the stress increases as we move away from the innersurface. Stress concentration factors should be used for both brittle and ductile materials. During quenching, a part will be cooled at a very fast rate using water or oil. Two sets of data werefound to have a normal distribution. Data set A has a mean of40 anda standard deviation of5. while dataset B has a mean of 42 and a standard deviation of 3. which of the following is true? a) All the data points ofset A arebigger than those ofset B b) All the data points ofset A are smaller than those ofset B (Q The same percentage of data points in sets A and B are smaller than 45 Tt Half of rhe data ooinrs in set B are smaller than 40 e) None ofthe above Name: Student #: key t- _+--_r ( 0.5 t"i^+t I \ ?d.h I F @ tF) @ fi) \:_-/ T t]' T T
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  • Spring '10
  • علاءحجازي
  • Trigraph, themaximum hear tress, themarimum hear tress, hant hoseo fset, nderp lanes tress, hear nd momentd

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