Which quantity changes the state of motion of an object?

The quantity that changes the state of motion of an object is force. According to Newton's laws of motion, specifically the second law, when a force is applied to an object, it causes the object to accelerate in the direction of the force. This acceleration represents a change in the object's velocity, which is directly related to its state of motion. Therefore, applying a force can increase, decrease, or change the direction of an object's motion.

Energy, while crucial in understanding the behavior of objects, does not directly change the state of motion by itself. Instead, it is often the result of doing work on an object, which involves applying force over a distance. Distance measures the space covered by an object during its motion, but does not inherently change that motion. Momentum is a property of moving objects, related to both their mass and velocity, but simply having momentum does not signify a change in motion; changes in momentum occur as a result of applied forces. Thus, force is the fundamental quantity responsible for altering an object's state of motion.