so (0,1) is the look vector, and i can move down the y axis....but what does the scalar x represent? speed?
Now say you want to move straight along the y-axis at speed x, this would give you a movement vector or velocity vector. In this case the velocity vector could be x*(0, 1) (x being a scalar). Think about what this means...what part of that formula tells you the direction of the movement and what part tells you about the speed of the movement? Now what would the speed of the velocity vector (2, 2) be?