Final answer:
Masses in motion is a concept studied under kinetics, which is a part of dynamics, a field of physics that deals with forces and motion. Kinetics includes the analysis of potential and kinetic energy along with other concepts like Newton's Laws, momentum, and collision.
Step-by-step explanation:
The subject matter of the question pertains to masses in motion. The correct term for the study of masses in motion within the provided options is kinetics, which is a part of the broader field of physics known as dynamics. Dynamics is concerned with the forces that cause objects to move, and kinetics, specifically, deals with the description and analysis of motion. This includes understanding both potential and kinetic energy. Potential energy refers to the stored energy in an object due to its position or configuration, while kinetic energy is the energy of an object due to its motion. Dynamics also encompasses other concepts such as Newton's Laws of Motion, work, energy, linear momentum, collision, heat transfer, and more.