For a pair of gears the allowable contact stress number for the pinion is 72 ksi and the allowable bending stress number for the gear is 50 Ksi Determine
a) The minimum required hardness of the pinion for Grade 2 steel: HB
b) The minimum required hardness of the gear for Grade 2 steel: HB

Steel is coated with a thin layer of ceramic to protect against corrosion. what do you expect to happen to the coating when the temperature of the steel is increased significantly? explain.

The higher the astm grain-size number, the coarser the grain is. a)-true b)-false

A-mn has a cubic structure with a0 0.8931 nm and a density of 7.47 g/cm3. b-mn has a different cubic structure, with a0 0.6326 nm and a density of 7.26 g/cm3. the atomic weight of manganese is 54.938 g/mol and the atomic radius is 0.112 nm. determine the percent volume change that would occur if a-mn transforms to b-mn.