In physics, a force is any interaction that, when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity to accelerate. Force can also be described intuitively as a push or a pull. A force has both magnitude and direction, making it a vector quantity.
Capsaicin is the chemical in the peppers, and then milk reverses it by using casein (A fat loving compound) to bond to the capsaicin and wash it away. Hope this helps!