Vector Addition

Questions: 1) Is vector addition commutative? Explain why or why not. 2) Explain, in you own words, how to add any 2 vectors geometrically. 3) Is it ever possible for the resultant (sum) of two vectors to be the zero vector? If so, describe the relationship that must be true between these 2 vectors. 4) Can you devise a geometric method (like the one above) to subtract 2 vectors? If so, how would you do this?