Open position guitar power chords contain at least one open string and therefore
can only be played in one place.
The root of this power chord is E, the open 6th string.
Also remember let your 1st finger touch lightly ( without
pressing down ) the strings that you do not want to hear.
The root of this pwer chord is A, the open 5th string.
The root of this power chord is D, the open 4th string.