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Unformatted text preview: continued on page 10 Last Name:___ ________________ First Name: ______________________ Student ID#: _________________________ MATERIALS 1M03 FINAL EXAM, 2008 This test contains 24 questions (18 MC and 6 long answer). You are responsible for ensuring that your copy of the paper is complete. Bring any discrepancy to the attention of your invigilator. SPECIAL INSTRUCTIONS: Aids allowed: 1 double-sided page crib sheet, nominally 8½ by 11 in. McMaster standard Casio FX-991 calculator Answer all multiple choice questions on the special answer sheet only. Answer all written questions on the examination copy. Be sure to show your work (where applicable) so that part marks can be awarded for incomplete answers. Be sure to include units with all answers that require them. Useful constants: Gas constant, R = 8.31 J/mol-K Charge per electron, e = 1.6 x 10-19 C Avogadro’s number, N A = 6.02 x 10 23 Boltzmann’s constant, k = 1.38 x 10-23 J/atom-K = 8.62 x 10-5 eV/atom-K 1cal =4.184J MC Q19 Q20 Q21 Q22 Q23 Q24 Total continued on page 10 Part A: This part consists of eighteen multiple choice questions, worth 2 marks each. In each case, put your answers on the scan sheet (marked McMaster University Examination Answer Sheet). Read the Marking Directions on this sheet carefully before starting. 1. A tie-rod in a car needs to support a force of 10.0 kN without yielding. Engineers are considering three different materials for this application; an advanced steel with a yield stress of 600 MPa and density of 7.80 g/cm3, an aluminum alloy with a yield stress of 190 MPa and density of 2.70 g/cm3 and a Mg alloy with a yield stress of 125 MPa and density of 1.74 g/cm3. Which of these materials will result in the lightest tie-road that can sustain the above force? (Hint: The length of the rod is the same for all materials, but the diameter may be different). (a) The steel (b) The Aluminum alloy (c) The Mg alloy (d) They all result in the same tie-rod mass. 2. A plate of steel 1.5mm thick has nitrogen atmosphere on both sides at a temperature of 1200C and is permitted to achieve steady state diffusion. The diffusion coefficient of nitrogen in steel at this temperature is -11 2 6×10 m /s , and the diffusion flux is measured to be -7 2 1.2×10 kg/m -s . It is also known that the concentration of nitrogen on the high pressure surface is 2 4kg/m ,How far into the plate from the high pressure side will the concentration be 2 1.8kg/m a. 1mm b. 1.1mm Å answer c. 1.3mm d. 1.4mm e. 0.9mm 3. The dislocation density has units of:...
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This note was uploaded on 02/13/2010 for the course ENGINEERIN 1m03 taught by Professor Porove during the Spring '10 term at McMaster University.
- Spring '10