It is our everyday experience that objects around us move from place to place. In kinematics motion is described in terms of position, velocity, and acceleration without considering what might cause bodies to move the way that they do. For example, why does a dropped feather fall more slowly than a dropped baseball? Why does a ball projected vertically upward come to rest at it reaches the maximum height? The answers to such questions take us into the subject of dynamics, the relationship of motion to the forces that cause it. Dynamics deals with the effects of forces on objects.

Before you can predict or explain the motion of an object, it is important to first understand what a force is and how to measure and calculate the sum of all forces acting on an object.

Key terms

• Kinematics: study of motion without regard to the cause of motion.
• Dynamics: deals with effects of a force on objects.