Obviously, a smart phone has very little gravity to it. And from what I've looked up, you could turn anything into a black hole if you get it dense enough. Let's assume my phone turned into a black hole, and I'm standing 5 feet away from it. The equation for gravity is F = G((mm)/r^2) right??? So according to this, since the mass would be the exact same if it got super dense, my black hole phone, will have no more force exerted on me than just my phone... right? Am I being stupid? r is the distance between them right?