It's common to hear people say that gravity is a "weak force" and that it is "32 times weaker than the weak nuclear force." But what does that even mean, if it has any meaning at all. The gravity on a particle is proportional to its mass. The electric force on an object is proportional to its charge. To make a statement about relative strengths, that would mean you're making an implicit statement about the relationship between an object's charge and mass, right?