Chisels and razors are good examples of a true "push cut", in which the blade functions as a very sharp wedge to part the material. In a slicing cut you get the wedge effect coupled with a sawing action, a good reason some folks like a "toothier" edge on their slicers.
Already some good observations on why straight razors are hollow ground, but I'd like to add that many early razors, and some still in use today, are flat ground, not hollow ground. I own a couple (both were made in Sheffield) and they shave just fine. They take a slightly different approach when honing/stropping, in that you have to raise the spine up slightly when honing and use a slackened strop technique, something you'd never, ever, do to a hollow ground razor. Still, I'm convinced that tinkering around with those old flat ground straight razors was good for my education. If you can learn how to sharpen them properly for shaving, you can apply the same techniques to just about any good knife. 'Course, to find those techniques, you gots to do research, lots and lots of research. But heck, that's half the fun ain't it? What better kind of treasure hunt than one in which the treasure is knowledge?
Sarge
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