Dot & Cross Products

Dot & Cross Products : Dot & Cross Products Dave McCallister Beechwood High School Physics

Dot Product : Dot Product A • B = |A| |B| cos θ A • B = Ax Bx + Ay By θ is defined as the angle between A and B States the component of one vector that points in the direction of the other vector Note: A • B = B • A Also known as scalar product

Cross Product : Cross Product A x B = |A| |B| sin θ |A x B| = Ax By – Ay Bx Direction of A x B is determined by Right Hand Rule Index finger points along A, Middle finger points along B, Thumb will point in direction of A x B Also known as vector product Note: A x B ≠ B x A

Cross Product : Cross Product

Practice : Practice Let A = 5 i + 4 j; B = 3 i + 2 j Find: A • B (5)(3) + (4)(2) 23 A x B (5)(2)-(4)(3) -2 k