How does height affect force?

Answer 1

Since force equals mass x acceleration (F=MA), the greater the height of a dropped object the more it will accelerate before it hits the ground, so the greater the energy it will hit with. So, more height, more energy. If one wants to stop a certain object with a certain amount of energy in a given time span, one needs more force if the energy level of the object is higher.

Another aspect is that force decreases with height (measured from earth): mass is constant, but gravitational constant decreases with distance to earth.