View Single Post
DaleSpam
#10
Jun11-09, 02:33 PM
Mentor
P: 16,967
You can look at this through conservation principles also. Consider this to be a plastic collision between the earth and the person.

Conservation of momentum: due to the mass of the earth there is negligible acceleration of the earth, the deceleration of the person is quite high. The final velocity of the earth and the person is approximately 0 after the collision.

Conservation of energy: this is a plastic collision where the KE goes almost entirely into deformation of the earth and the person. If the earth is highly deformable (e.g. water or cushion) then the energy will go into deforming the earth, if the earth is very rigid (e.g. concrete) then the energy will go into deforming the person. This is usually a bad thing for the person as blood vessels etc. don't work well when deformed as described by berkman.