The weakest forces of interaction among all classified fundamental forces are?

1. Forces are classified into four categories gravitational, electromagnetic, strong nuclear, and weak force.
2. Among these forces gravitational force has the lowest constant of proportionality $G=6.674\times {10}^{-11}{m}^{3}k{g}^{-3}{s}^{-2}$
3. Hence, gravitational force is the weakest of all classified fundamental forces.