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What does it mean to say

Answer 1

The gravitational force exerted by a black hole is strong because the force is proportional to the mass and the black hole as a large mass. In the same way, the gravitational field of the Earth may beat a weak enough magnet - because the Earth is large and the magnet is small and we're comparing apples and oranges.

But fundamentally speaking, among particles with masses that correspond to elementary particles, gravity is the weakest force. For example, the gravitational force between two electrons is 1043 times weaker than the electrostatic one. The weak nuclear force is as strong as the electromagnetic one at very short distances - but exponentially drops at distances much longer than the W-boson wavelength. The strong nuclear force is the strongest among the four forces.

It seems that the weakness of gravity relatively to all other forces, when evaluated at the level of elementary particles, is a general principle that has to hold in any consistent quantum theory of gravity, see

http://arxiv.org/abs/hep-th/0601001