What does force describe in physics?

In physics, force is defined as an interaction that, when unopposed, will change the motion of an object. It is a vector quantity, which means it has both magnitude and direction. The correct answer reflects this definition as it emphasizes that force describes the specific push or pull acting on an object. This push or pull can cause an object to accelerate, decelerate, remain in place, or change direction, thus fundamentally influencing its motion and state of rest.

Other choices describe different concepts related to motion or distance but do not encapsulate the essence of what force is. Speed refers only to how fast an object is moving, without any regard to the direction. The total distance traveled is a measure of how far an object has gone, which does not inherently involve any force. The direction of an object's motion indicates where the object is heading but does not capture the influence of force on that motion. Therefore, focusing on the force acting on the object directly addresses how motion is affected, making it the most accurate choice.