Force is directly related to motion according to Newton's second law of motion. According to this law, the acceleration of an object is directly proportional to the net force applied to it and inversely proportional to its mass. Mathematically, this can be represented as:
F = ma
where F is the force applied on the object, m is the mass of the object, and a is the acceleration produced.
In simpler terms, if a force is applied to an object, it will cause the object to accelerate. The magnitude of the acceleration depends on the mass of the object - lighter objects will experience larger accelerations for the same force applied compared to heavier objects. Therefore, force is necessary to overcome inertia (tendency of objects to resist changes in their state of motion) and induce motion in an object.