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That's a pretty thin phone book - ours are about 8cm thick. I think the same technique would still work, though - the real key is not to be ripping the entire thickness of the book at once.
I saw an 80+ year old guy rip at least 15 local (Portland) phonebooks in half in some kind of record time, during a Blazers half time show. Unlike the guy in the link, he credited Jesus, not trickery to his feats of strength.