The parallelogram law of vectors states that if two vectors are represented by the sides of a parallelogram with a common starting point, then the resultant vector is represented by the diagonal of the parallelogram passing through that common starting point.
To illustrate this, suppose we have two vectors, vector A and vector B, with the same starting point. We can represent vector A by one side of the parallelogram and vector B by another side. The remaining sides of the parallelogram will represent the negative of each vector (-A and -B).
Now, if we connect the common starting point with the opposite vertex of the parallelogram, that diagonal represents the resultant vector (vector R). Vector R is the sum of vector A and vector B.
Mathematically, the parallelogram law can be stated as:
R = A + B
where R is the resultant vector, A is the first vector, and B is the second vector.
This law is based on the concept of vector addition, which involves adding the corresponding components of the vectors together. By applying the parallelogram law, we can determine the magnitude and direction of the resultant vector in a step-by-step manner.