Mid-term exam 04

# Mid-term exam 04 - NAME MATERIALS SELECTION 530.352 th FALL SEMESTER PROF K.J HEMKER MID-TERM EXAMINATION(Closed book closed notes open mind

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NAME: ________________________________ MATERIALS SELECTION FALL SEMESTER 530.352 PROF. K.J. HEMKER MID-TERM EXAMINATION (Closed book - closed notes - open mind) October 18 th , 2004 1. We have studied materials on various length scales in order to understand why materials have the properties they do. Consider the bike frame shown here, which is made of high strength Al. Al is FCC and has a lattice parameter (a o ) of 0.4nm; the grain size of the tubes used to make this frame is 3 µ m (assume cubic sized grains); the density of Al ( ρ Al ) is 2.7 Mg m -3 and the weigh of the frame is 1.6 kg. a. What is the total volume of Al in the frame? If you melted the frame down and poured it into a cube how big would the cube be on each side? (5 points) b. How many Al grains are there in the frame? (5 points) 530.352 Materials Selection Mid-term Exam Page 1 of 8

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530.352 Materials Selection Mid-term Exam Page 2 of 8 c. How many Al atoms per grain? (10 points) d. How many Al atoms per frame? (5 points)
2. The NASA Institute for Advanced Concepts has proposed building a Space Elevator as pictured here. The “elevator” will be held in place by the centrifugal forces associated with the mass of the cable, a proof mass to be placed at the end and the rotation of the earth. It has been suggested that the proof mass will not be needed once the elevator

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## This note was uploaded on 04/08/2008 for the course MECHENG 352 taught by Professor Hemker during the Spring '08 term at Johns Hopkins.

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Mid-term exam 04 - NAME MATERIALS SELECTION 530.352 th FALL SEMESTER PROF K.J HEMKER MID-TERM EXAMINATION(Closed book closed notes open mind

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