Green said
How exactly is a tank going to be doing any dodging whatsoever? It can't duck, jump, and has to spend considerable time to turn it's chassis around if it intends to go anywhere but forward (and even then it's still going in a single direction) - anti-armor bazooka shots don't really travel slowly, so there's that. It could always shoot it down, sure. If the projectile was non-explosive in nature (like, say a Railgun), then that wouldn't work out very well either. Hiding from a projectile already shot towards it doesn't make much sense. I don't know what ERA is, please elaborate.
Standard reactive armor uses slabs of explosive sandwiched between two plates of metal. When a projectile impacts this unique armor, the explosive detonates, causing the plates to force apart, in turn damaging standard ammunition, kinetic-penetrator rods (the plates break the rods up, as they're rather brittle) and disrupts the metallic jet generated by a shaped-charge.
ERA is different. It's a type of armor that works like a giant capacitor, where an electromagnetic current is passed through two sheets of material separated by an insulator. When a round strikes the armor, a powerful current is driven into the projectile, either vaporizing it or turning it into a plasma. It's newly-developed stuff, so its true method of operation is classified as hell as far as I know.
http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220060011057%22.PGNR.&OS=DN/20060011057&RS=DN/20060011057http://www.telegraph.co.uk/technology/3298279/Electric-armour-vaporises-anti-tank-grenades-and-shells.htmlAs for railguns, shooting that down is a matter of firing a potent particle beam at it or firing an intercepting projectile at it (like a shell or dart, which would knock the incoming round off course or break it up). This is dipping into hard physics (and thus we're treading into uncharted waters), but particle beams of sufficient power transfer direct thermal energy to the molecules a target is made up of---superheating it if you will. The shell would more or less explode. That or fry its guidance systems if it's a smart projectile and not a dumb one, due to the electronic interference and radiation generated by the beam's impact upon the metal projectile.
Hiding works if the enemy hasn't spotted you yet (or if they have, requiring your stealth capability is an option as well, such as using buildings for cover---especially if you're fighting at night). Sometimes the best way of dealing with damage is to simply not be seen.
As for the movement restrictions associated with treads, we could go with a hover tank, but those are just flat-out heresy. Everyone knows treads are superior.