This isn't homework...I was just thinking through this rather morbid scenario and realised that I couldn't remember how to calculate the result I was looking for. The morbid scenario is person falling from a building of height h. How do you calculate the force exerted on the person by the ground when he/she hits it? Obviously, it is easy enough to calculate the maximum velocity the person will achieve just before hitting the ground. From this, we can determine his or her change in momentum from mv_max to zero. But without knowing the time over which the force acts (very small, to be sure), how could we calculate the force of impact?