question_answer

                Answer the following : (a) Among the known types of forces in nature, the gravitational force is the weakest. Why then does it play a dominant role for motion of bodies on the terrestrial, astronomical and cosmological scale? (b) Do the forces of friction and other contact forces arise due to gravitational attraction? If not, what is the origin of these forces?

Answer:

                (a) The strong nuclear forces operate only over a range of distance of the order of \[{{10}^{-14}}\] to \[{{10}^{-15}}m.\]. The forces involved in weak interactions operate only during radioactive decay. Electrical forces are stronger than gravitational forces for a given distance, but they can be attractive as well as repulsive unlike gravitational force, which is always attractive. As a result, the forces between massive neutral bodies are predominantly gravitational.                 (b) No, the forces of friction and other contact forces have electromagnetic origin.