ABSTRACT
Two-dimensional curvilinear motion can be analyzed by using rectangular components of motion. The ball rolling in a straight line along the side of the table, designated as the x-direction, is moving in one dimension. A special case of projectile motion in one dimension occurs when an object is projected vertically upward. General two-dimensional projectile motion is in free fall too, because the only acceleration of a projectile is that due to gravity. If, however, the acceleration is at some angle other than 0° or 180° to the velocity vector, the motion will be along a curved path. When the velocities are linear in the same or opposite directions and all have the same reference, the relative velocities can be found by using vector subtraction. Many physical quantities, including those describing motion, have a direction associated with them – that is, they are vectors.
