Vice President Joe Biden has switched sides here in Philadelphia, so it’s time for five what-to-watch-for halftime items: 1. Noah’s numbers: Navy sophomore Noah Copeland has carried 15 times already for 81 yards and his team’s only touchdown. He’s never carried more than 21 times in a game. Will fatigue set in, or is fatigue not an option in this game? 2. Step up and stop: Aside from Josh Tate’s fumble-forcing hit on Army’s Raymond Maples, neither team has had a breakout defensive play. Who’ll snare the first interception or break off the first big fumble return? 3. Old rivals,…