Newton's Second Law states that the relationship between mass and acceleration is expressed by the equation \( F = ma \), indicating that the net force acting on an object is equal to the product of its mass and its acceleration, showing that larger masses require greater forces to achieve the same acceleration.
The vertical net force acting on the box is determined by the difference between the upward force (like normal force) and the downward force (like gravity).
The horizontal net force acting on the box is the sum of all horizontal forces acting on it, accounting for any applied forces minus friction or other resisting forces.