1. The US was a neutral power during the hunt for the Bismarck. Which is to put in a short answer, no, the US was not in position to destroy the Bismarck unless it entered the war first (with the small caveat that the US WAS becoming increasingly aggressive in "defensive" measures, but it's doubtful the Bismarck would have put into position to provoke a fleet engagement with the USN).

2. The US Atlantic fleet was fairly sizable in 1941. What it suffered from was a lack of modernization however, with much of it's battleship component having last been updated in the early 1930's. While in terms of firepower and protection they might have been up to the task, the US battleships of the Atlantic fleet were a lot slower than the Bismarck. The interesting capabilities the US Navy did have on hand in the Atlantic however would have been the USS Yorktown, Wasp, and Ranger (and USS Hornet if the Bismarck had sortied in very late 1941). This was not a small amount of airpower, and the Bismarck had already proven unequal to the task of defending itself against the much smaller, and worse equipped FAA.

This is all counter-factual to history of course. But for the historical answer, see point 1, for the counter historical, it's likely Bismarck vs USN would have played out similarly to history (airpower cripples Bismarck, surface action finishes it) or USN airpower might have been enough to do the job alone.