Final answer:
A Kerr black hole differs from a Schwarzschild black hole due to its rotation. The Kerr black hole has a rotating ring singularity and an ergosphere, none of which are present in the nonrotating Schwarzschild black hole. The rotation influences the black hole's event horizon and spacetime dynamics.
Step-by-step explanation:
A Kerr black hole is different from a Schwarzschild black hole primarily because of its rotation. The Schwarzschild black hole is the simplest kind, which does not rotate and has only mass as its charge. The event horizon of a Schwarzschild black hole, also known as the Schwarzschild radius (Rs), is determined by the formula Rs = 2GM/c2 where G is the gravitational constant, M is the mass of the black hole, and c is the speed of light.
On the other hand, a Kerr black hole includes rotation as an additional parameter. The rotation causes the event horizon to be shaped differently and produces a region outside of the event horizon known as the ergosphere, where objects can theoretically be pulled along by the black hole's rotation but still have a chance to escape.
Unlike Schwarzschild black holes, Kerr black holes have no singularity that can be touched by an outside observer since the singularity would form a ring due to the rotation. Furthermore, the Kerr black hole's event horizon and the size of the ergosphere would reduce as the rate of rotation increases.
Overall, the key differences lie in rotation and the related dynamics of spacetime around the black hole. The Schwarzschild black hole is nonrotating, while the Kerr black hole is characterized by its rotating nature which introduces unique phenomena such as the ergosphere.