In the parallelogram of vectors method

Scalars & Vectors - OCR A-Level Physics

  • In the parallelogram of vectorsA method for adding two vectors: draw them from the same point and complete the parallelogram; the diagonal is the resultant. method, both vectors are drawn from the same point.
  • Complete the parallelogram using the two vectors as adjacent sides.
  • The resultantThe single vector that has the same effect as two or more vectors acting together. is the diagonal of the parallelogram from the common origin.
  • This method is equivalent to the triangle method -- both give the same resultant.
  • The parallelogram method is often used when forces act at the same point on an object.
  • For two vectors at right angles (90 degrees), the parallelogram is a rectangle.
  • Use Pythagoras to find the resultant magnitude and trigonometry for the angle.
  • For vectors at other angles, use the cosine ruleA trigonometric rule for non-right-angled triangles: c² = a² + b² − 2ab cos C.: \(R^{2}\) = \(A^{2}\) + \(B^{2}\) - 2AB cos(180 - theta), where theta is the angle between the vectors.
Scalars & Vectors Overview
Vectors cannot be added like ordinary numbers unless they act along the same line 3 of 10 Any single vector can be split into two perpendicular components