Adding one tip on top of what mouser said and linked to:
You can also make a hotkey that copies selected text to clipboard but leaves the FARR search box empy on open.
Next you create an alias for Velocity (and one for any other tool you want to pass a selected string to).
In other words, instead of tying one hotkey to a single program, or to a single alias that lists a number of programs, you make a generic "copy selection and open FARR" hotkey and then set up any number of aliases that you want to use with it.