Which force is responsible for determining the state of motion of a body?

The force responsible for determining the state of motion of a body is the resultant force. The resultant force is the vector sum of all the forces acting on an object. It considers both the magnitude and direction of each individual force, allowing for a comprehensive analysis of how these forces interact.

When a body is subjected to multiple forces, the resultant force influences its acceleration and ultimately its motion according to Newton's second law of motion, which states that force equals mass times acceleration (F=ma). If the resultant force is greater than zero, the object will accelerate in the direction of that force. Conversely, if the resultant force is zero, the body either remains at rest or continues moving at a constant velocity, adhering to Newton's first law of motion.

Understanding the concept of the resultant is fundamental in engineering and physics since it helps in analyzing static and dynamic systems, making it easier to predict how structures and materials will respond to various force applications.