What do marine/maritime engineers do?

Thermal stresses are developed in a metal when its a) initial temperature is changed b) final temperature is changed c) density is changed d) thermal deformation is prevented e) expansion is prevented f) contraction is prevented

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

The proportional limit is always greater than the yield strength for a material. a)-trune b)- false