Which term is defined as the branch of mechanics dealing with the relationships between force and motion?

• A. Kinematics
• B. Mechanics
• C. Kinetics
• D. Biomechanics

Answer: (C)

This question tests understanding of how forces relate to movement, which is the domain of kinetics. Kinetics focuses on the forces that cause or influence motion—things like muscle contractions, joint torques, and external forces such as gravity or ground reaction forces—and explains how these forces lead to changes in speed, direction, and overall movement. For example, kinetics would analyze how a muscle generates a certain force to produce a given acceleration of a limb or how the ankle joint torque contributes to propulsion during walking.

In contrast, kinematics describes motion without considering what forces produce it—looking at shape, speed, direction, and timing of movement rather than why it occurs. Mechanics is the broader umbrella that includes both kinetics and kinematics, while biomechanics is the application of these mechanical principles to living systems. Since the focus here is specifically on the relationship between force and motion, the correct term is kinetics.