What is the name of the study of motion that focuses on why objects move?

Dynamics is the branch of physics that specifically examines the causes of motion—essentially, it looks at why objects move and what forces are acting on them. This field delves into concepts such as force, mass, and acceleration, forming a comprehensive understanding of how and why objects change their state of motion.

In contrast, kinematics is focused solely on the descriptions of motion itself, such as velocity and acceleration, without considering the forces that cause this motion. Mechanics is a broader term that encompasses both dynamics and kinematics, as well as other areas like fluid mechanics and thermodynamics. Statistics, on the other hand, is unrelated to the study of motion; it deals with data collection, analysis, interpretation, and presentation. Thus, the specific focus of dynamics on the forces and causes behind motion makes it the correct answer to the question.