3.2 Vector Addition and Subtraction: Graphical Methods

• In 2D, the direction of the vector is relative to the reference frame using an arrow with a length proportional to the vector's magnitude and direction.
• Head-to-Tail: graphical method of adding vectors
• following. The tail of the vector is the starting point of the vector, and the head (or tip) of a vector is the final, pointed end of the arrow
• A-B = A + (-B)
• multiplying a vector by a positive scalar = magnitude changes, direction stays the same.
• -scalar*vector changes vector’s magnitude and gives new vector the opposite direction.
• When vector A is multiplied by a scalar c,

  • the magnitude of the vector becomes the absolute value of c(A),
  • if c is positive, the direction of the vector does not change,
  • if c is negative, the direction is reversed.
• that division is the inverse of multiplication.
• When multiplying a vector by a positive scalar, the magnitude changes (You just multiply), and the direction stays the same
• If a vector is multiplied by a scalar quantity that is negative, the vector's magnitude and direction changes to the opposite direction