Here's a breakdown:

* Opposite Directions: The forces need to be pushing or pulling against each other.

* Same Line of Action: They need to be acting along the same straight line.

Example:

Imagine you're pushing a box to the right with a force of 10N. Someone else is pushing the box to the left with a force of 5N.

* Force 1: 10N to the right

* Force 2: 5N to the left

To find the net force acting on the box, you would subtract the smaller force from the larger force:

10N - 5N = 5N

The net force on the box is 5N to the right.

Key Points:

* Vector Subtraction: Force is a vector quantity, meaning it has both magnitude (size) and direction. When subtracting forces, you're essentially finding the resultant force, which is the single force that represents the combined effect of the two forces.

* Direction: The direction of the resultant force is determined by the direction of the larger force.

* Zero Net Force: If the two forces are equal in magnitude but opposite in direction, the net force is zero. The object will remain at rest or continue moving at a constant velocity.