Which branch of physics studies the relationship between thermal and mechanical energy?

Thermodynamics is the branch of physics that focuses on the relationships between thermal energy (heat) and mechanical energy (work). It explores how energy is transferred and transformed, particularly in systems where heat is involved. One of the core concepts of thermodynamics is the laws of energy conservation and conversion, which reveal how energy in the form of heat can influence physical processes and work done by or on a system. This branch provides a framework to understand phenomena such as heat engines, refrigerators, and the efficiency of various processes involving energy transformation.

Kinetics pertains to the study of motion and the forces that cause motion, but it does not specifically address how thermal energy relates to mechanical energy. Dynamics, while related to forces and motion, also does not encompass the specific heat-energy relationships found in thermodynamics. Aerodynamics deals with the behavior of air as it interacts with solid objects, primarily focusing on forces like lift and drag rather than the heat-energy relationship.

Therefore, thermodynamics is the most suitable and accurate branch of physics that addresses the connections between thermal and mechanical energy.