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 - Good Luck! (12 pointsl l. For the flowing statements circle the conect answer. Ceramics are brittle and much stronger in compression than in tension. Thermoset polymers can be melted and reformed. The factor of safety is dbfined as the ratio of strength to stress. If30 parts fail out ofeach 100 parts, this means that the reliability is 0.3. Cold working 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 inner surface. 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 were found to have a normal distribution. Data set A has a mean of40 and a 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 are bigger 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
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During a tensile test of some steel alloy, only the following three data points were recorded: or =200 MPa&er :0.001, o: = 300 MPa & sz =
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This note was uploaded on 10/25/2010 for the course MECHINCAL 2010 taught by Professor علاءحجازي during the Spring '10 term at Hashemite University.

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

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