A free-body diagram is a drawing of all external forces acting on a body Dynamics is the study of how forces affect the motion of objects, whereas kinematics simply describes the way objects move

External forces are any outside forces that act on a body.

newton — SI unit of force; 1 N is the force needed to accelerate an object with a mass of 1 kg at a rate of 1 m/s 2. free-body diagram — sketch showing all external forces acting on an object or system; the system is represented by a single isolated point, and the forces are represented by vectors extending…. force — push or pull on an object with a specific magnitude and direction; can be represented by vectors or expressed as a multiple of a standard force. external force — force acting on an object or system that originates outside of the object or system.