I am in the middle of physics debate with someone who has some rather, shall we say, unconventional views regarding classic mechanical physics. It started when he posted that he feels 9/11 was a conspiracy because a section of a building falling does not increase the "load" (as he called it) on the lower floors. Our rebuttal was well do you think a brick resting on your head exerts the same force as one that falls and hits you in the head and he said YES. I replied that yes, of course the force of impact is greater than when it is at rest and gave an example of a 5 kg bowling ball dropping 1 meter and fully stopping within .02m after impact, and I worked out the forces at rest. If you put a 5 kilogram bowling ball on a scale, you will get 5 kilos. Its weight (which is a force) 5 * 9.8 = 49 Newtons of force. F = M G Now lets take that 5 kg ball and drop it onto the scale from 1m high. Do you really think it will still only show 5kg upon impact? Of course not. It will impact the scale at velocity of 4.43m/s2, with a Kinetic energy of 49 Joules. KE = 1/2 MV^2 (4.43^2 *5 /2 ) = 49 joules. Here is one of the other concepts you are not understanding, its the Work/Energy principle, that the CHANGE in Kinetic energy is directly related to the amount of work done. You recognized a change in kinetic energy but disregarded it. Here is something else you did not take into account. When the object is DECELERATED (acceleration in the opposite direction), the longer the deceleration, the less of an impact force. If you catch something fast, is there a greater impact on your hand if your hand does not move, or it you give with the impact and the hand moves with it? So if we take that 49 Joules of kinetic energy, and it is equal to the work being done (work energy principle), so we can substitute KE for Work. Force * Distance = Kinetic energy which is 49 joules. We say that 49 Joules of work was expended over a deceleration of .02M upon impact with the scale. Force = 49N / .02m. Force = 2450 N - average force during impact (when decelerated within .02m) Compare that with 49N when at rest on scale.