Net force is the overall force acting on an object when all individual forces are combined. It determines how an object will move, whether it will accelerate, decelerate, or remain at rest. If the net force is zero, the object will not change its state of motion. For example, if two people push a box in opposite directions with equal strength, the forces cancel each other out, resulting in a net force of zero. Conversely, if one person pushes harder than the other, the box will move in the direction of the stronger push, indicating a net force in that direction.