## incorrect calculator?

I believe that this calculator generates answers assuming that the only force acting on a falling object after it has encountered a stopping surface is the force of the stopping surface. The calculator needs to factor in gravity throughout the whole fall. Would someone else please verify?
http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html
Click Mechanics, work-energy principle, and then impact force of falling object, and "Since you know velocity, mass, and kinetic energy, can you predict the force of impact?"
Example numbers:
m=50kg, h=10m, d=5m
stopping force should be about 1480N, but the calculator is saying 980N.

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Read the little note at the bottom of that page.

 Note that the above calculation of impact force is accurate only if the height h includes the stopping distance, since the process of penetration is further decreasing its gravitational potential energy.
That should take care of your problem (you probably should use d=5, h=5 to describe the situation I think you have in mind). If not for this disclaimer, the calculation would be, as you point out, wrong for the general case where d is not necessarily small compared to h.
 I didn't take time to read that disclaimer carefully. Thanks for the quick answer!

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