Eng ek 301- lecture 2: multiplication and division of a vector by scalar, vector addition. When adding two vectors together, it is important to account for both their magnitude and their directions. The resultant force from the two vectors can be obtained by drawing a parallelogram of forces as shown in the figures below where r is the resultant force of vector a + vector b: vector subtraction. The resultant of the difference between two vectors a and b of the same type may be expressed as: finding the components of a force, sometimes, it is more useful to resolve a force into two components. Eng ek 301- lecture 3: addition of a system of coplanar forces, a force can be decomposed into two components along the x and y- axis. For analytical work, these components can be represented in either scalar or cartesian vector notation. a. i. Scalar notation: f = fx + fy a. ii.