Final answer:
The gravitational force becomes noticeable depending on the mass of the objects and their proximity; it's significant for large masses like planets and stars but negligible for small particles.
Step-by-step explanation:
The gravitational force between two objects becomes noticeable when the mass of the objects is sufficiently large and the distance between them is relatively small. On a small scale, such as between individual charged particles, gravity is negligible because electric and magnetic forces dominate. However, on a larger scale, the effect of gravity predominates because it is always attractive, and other forces like the electromagnetic forces largely cancel out due to objects being electrically neutral. An ordinary human being experiences a significant gravitational force from the Earth, which is why a fall from even a few feet can be dangerous. Moreover, in the context of astronomy, gravity is the principal force determining the motion of planets, stars, and galaxies, despite being the weakest of the four fundamental forces.