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.
This chapter deals with forces and how they affect motion. The quantity of motion is called momentum. Momentum is the product of mass and velocity. When objects collide the momentum is conserved. The total momentum of a system will not change unless an external force acts on it.