vector
Vectors in Two Dimensions A vector is a quantity that has magnitude and direction. Displacement, velocity, acceleration, and force, for example, are all vectors. In one-dimensional, or straight-line, motion, the direction of a vector can be given simply by a plus or minus sign. In two dimensions 2-d , however, we specify the direction of a vector relative to some reference frame i. , coordinate system , using an arrow having length proportional to the vectors magnitude and pointing in the direction of the vector. Figure 3.9 shows such a graphical representation of a vector, using as an example the total displacement for the person walking in a city considered in Kinematics in Two Dimensions: An Introduction. We shall use the notation that a boldface symbol, such as D , stands for a vector. Its magnitude is represented by the symbol in italics, D , and its direction by . Vectors in this Text In this text, we will represent a vector with a boldface variable. For example, we will represent the quantity force with the vector F , which has both magnitude and direction. The magnitude of the vector will be represented by a variable in italics, such as.