this is just my humble opinion after carrying, and woods-bumming with
hawks, hatchets, and
axes for almost 42 years, all over the planet, and building them for almost as long
(made my first river-rock caveman axe when i was five, with a broken weathered branch and some rawhide string - it finally fell apart when it was thirty-something - i used to crush rocks with it.). 
:thumbup:
a proper hawk is
long, and has an ounce of weight per inch of length, give or take ten percent, while
a hatchet is heavier per inch (pretty much just a scaled-down axe.).
a balanced tomahawk has its
CG where the top third meets the middle third, and
the hand wants to sit idle where the bottom third meets the middle third - the
butt end acts as ballast in that hold, and as a
second hand-hold in power strikes and door entries, and also is a
complementary weapon to the head of the hawk in
single-hand good hawk combatives.
a hatchet's CG is
in, or
nearer to, the
head than a tomahawk, and the bit of a hatchet is usually
wedge-shaped in cross-section, rather than
knife-like, in a proper hawk's case.
a proper hawk has a diminutive bit edge,
1" to 2 1/2", which
penetrates with little effort.
a proper hatchet
(that may be used in place of a hawk. among other specialty hatchets) will have a larger edge,
2 1/2 to 3 1/2 inches.
a hatchet hacks.
a tomahawk pecks.
a hatchet
splits.
a tomahawk
interrupts.
a hatchet is very nice to have along on a hike,
but has less use per mile of effort IME than a proper long tomahawk (of the same weight) does, for how much effort the two are comparitively
to carry.
other views are certainly applauded for varying from this one, as far as i am concerned however.
if i thought i knew everything about choppers,
i'd stop developing by now.
good question, brother!
vec