What is the angle between vectorA and vectorB if vectorA and vectorB denote the adjacent sides of a

Question

(a) What is the angle between vectorA and vectorB if vectorA and vectorB denote the adjacent sides of a parallelogram drawn form a point and the area of the parallelogram is (1/2)AB?

(b) State and prove triangular law of vector addition?

Answer 1

(a) Area of a parallelogram 

Area of parallelogram = A B Sin  θ (Applying cross product)

Given, area of parallelogram = (1/2)AB

(b) Triangular law of vector addition states that if two vectors can be represented both in magnitude and direction by the sides of a triangle taken in order then their resultant is given by the third side of the triangle taken in opposite order.