Final answer:
The net force when adding forces of 18N, 12N, and 30N depends on their directions. Assuming they act along the same line, the net force is 60N.
Step-by-step explanation:
If you are referring to the net force when combining forces of 18N, 12N, and 30N, it depends on the direction in which each force is acting. In physics, force is a vector quantity, which means it has both magnitude and direction. If all three forces act in the same direction, you simply add their magnitudes together to get the net force. However, if they act in different directions, you would need to take these directions into account and possibly use vector addition to correctly calculate the net force.
For simplicity, assuming all forces act along the same line, the net force would be the sum of the three forces:
Net Force = 18N + 12N + 30N = 60N
This is the simplest case. If the forces act in different directions, more information would be needed to determine the net force.