This chapter covers the basic units of the Metric System. The entire field of physics requires seven fundamental physical quantities. Practice is provided to learn how to express measured quantities. The Nature of Motion Motion can be described in terms of velocity, acceleration, and the position of an object. Velocity describes both the speed and direction of an object.
Acceleration is the change in velocity per unit of time.
Vectors A vector is characterized by both magnitude and direction. A force is a vector quantity because a force must act in some direction. Scalar quantities have magnitude only. Motion and Force Force is defined as a push or a pull. Dynamics is the study of forces and the motion that results.