Two-Dimensional Motion

• two-dimensional motion is more common, but harder to analyse than uniform motion
• even if speed remains the same, a simple change in direction would make uniform motion into two-dimensional motion
• resultant displacement

  vector sum of the individual displacements

  to add vectors, use the tip to tail method
• average velocity in two dimensions

  the resultant displacement divided by the time interval
• relative motion


  the velocity of an object relative to a particular frame of reference