Seriously, learn the very basics ("learn how the universe works" as I like to put it), for which I think there's no substitute, and what I'm saying will be clear. Or maybe find a "physics for poets" text that goes into these details, but that's an appeal to authority.
http://www.amazon.com/Sears-Zemanskys-University-Physics-10t... (Inexpensive older edition that's a good choice for self-study; see also the associated Study Guides and Student Solutions Manuals).
Seriously, learn the very basics ("learn how the universe works" as I like to put it), for which I think there's no substitute, and what I'm saying will be clear. Or maybe find a "physics for poets" text that goes into these details, but that's an appeal to authority.