The Arcane Strike feat says that
your weapons [...] are treated as magic for the purpose of overcoming damage reduction.
I do not read this as suggesting that a mundane weapon actually becomes magical - for instance, it would presumably still not be found by detect magic.
An incorporeal creature is "immune to all nonmagical attack forms", and can only be struck by "magic weapons".
Does this mean that with Arcane Strike, an otherwise nonmagical weapon can be effective against an incorporeal enemy?