http://www.youtube.com/watch?v=5C5_dOEyAfk :ahhh:
Sorry if this seems patronizing (and that it's off topic), but this video demonstrates the effect of air resistance on falling objects (or a lack of air resistance on the moon due to there being no atmosphere). That's why the hammer falls at the same speed as the feather, they both have a downward force of 1.6 Newtons with no opposing force to alter their speed. If you knew that then sorry for being a [censored], but I like being pedantic
Edit: On Topic
I don't much care for the encumbrance number, so long as they give me a way in which I can lug all my shhhit around after looting and robbing everything. Thief's gotta make money somehow