The biggest difference between one-dimensional and two- or three-dimensional motion involves the direction. Remember that displacement, velocity, and acceleration are all vector quantities and that in one dimension we satisfied the direction requirement with either a positive or negative sign.
However, to completely describe motion in two or three dimensions, we must incorporate vectors. This means that all the vector operations discussed in Chapter 4 can be applied to displacement, velocity, and acceleration. Believe it or not, this section has no new information. It simply combines the concepts of motion discussed in Chapter 8, “Motion in One Dimension,” with the vector operations discussed in Chapter 4.
Let's start by revisiting ...