The question was "If i have a domain name www.footballbaseball.com does Google recognise these are two separate keywords or does it lump them together as one?
I pay very close attention to this and Google will see the individual words since it is a domain name. Same applies to "most" file naming too. It doesn't appear that those hyphens are needed anymore but I am not giving them up just yet. ;)
Also, domains are not case sensitive. To help visitors read continuous strings a little easier, I like using PascalCasing now. So the above would end up being FootballBaseball.com.
P.S. In your example, you've got an extra kick in the arse. Note the word Baseball? And then note the word Baseball backwards? That's double mint! ballBaseball