It's a method of using chalk scraped across your tires and driving a short distance and observing where the chalk disappears, rinse, repeat, until the wear is fairly even. In theory, you can use the chalk wear to identify the correct pressure for your exact tires. Here is a video (a bit goofy but effective) that explains it.Chalk test?
Probably about 32-34 PIS. they will fluctuate throughout the day around 2-4 PSI either way depending on outside temp and road temp. The more you drive the hotter the tire = Increase in pressure. Reread you College Physics books.