We must forces to calculate net force if the forces are going in OPPOSITE directions. options:
add
or
subtract

subtract

Explanation:

To find the net force of two bodies going in opposite directions, we must subtract the forces this is because they are not additive forces.

The net force is the resultant force acting on a body. This resultant force is the single force that will produce the same effects as all given forces. When forces are directed oppositely on a body, they are subtracted from each other to find the net force.

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