Assume gears are readily available in face-width increments of 0.5 in (i. e. 2.0 in, 2.5 in. 3.0 in, 3.5 in.), with face widths in the range of three to five times the circular pitch. Specify a diametral pitch and face width such that the minimum WEAR factor of safety for the pinion is equal to 1.3.

On solidification from a melt, the polymer polyethylene forms a semi-crystalline spherulite structure. (i) sketch an individual spherulite and label the amorphous and crystalline regions. (ii) draw a schematic to show the changes in specific volume with temperature during cooling from the melt, comparing it to the theoretical extremes of fully crystalline and fully amorphous (indicate tm and tg)