The Forces     We all know that the gravity of a black hole is incredibly strong, but how strong is strong? The thing about black holes is that they have almost no size, the technically occupy nearly no space themselves, this means that r, the radius at which an object can be to the center of the black hole can be tiny. This allows the force to become massive, which is shown in this equation, F = (G(m1)(m2))/r^2.  G = gravitational constant, m1 = mass of object 1, m2 = mass of object 2.     With the "mass" of a black hole being astronomical, it doesn't take a very small radius to get a huge force.  In fact, the radius after which nothing can escape the gravitational force is called the event horizon.  The distance from the center of the black hole, the singularity, at which the event horizon starts is defined by the Schwarzschild Equation, R = (2mG)/c^2.  (hyperphysics).  So a black hole with the mass of the Earth would have an event horizon size of only 0.89 m!      The forces acting inside the event horizon are spectacular in how the effect matter, the acceleration an object feels is huge.  Objects get stretched out as they get closer and closer to the singularity, and torn apart completly and converted into pure energy at the point of the singularity.