Which branch of mechanics studies changes in the motion of objects due to forces acting on them?

The correct choice is dynamics, which is the branch of mechanics that deals with the study of forces and the resulting motion of objects. Dynamics analyzes how forces impact the behavior of objects, determining how they accelerate, decelerate, and move in response to those forces. This includes the examination of various types of forces, such as gravitational, frictional, and applied forces, and how they influence the motion of an object over time.

In contrast, kinematics focuses solely on the description of motion, such as displacement, velocity, and acceleration, without considering the forces that cause this motion. Statical mechanics concerns itself with objects at rest and forces in equilibrium, while aerodynamics specifically studies the behavior of air and other gases in motion, particularly in relation to solid objects like aircraft. Therefore, dynamics is the most appropriate choice for understanding how forces affect motion.