Here's my situation... I have a loader dumping rock onto a proposed screening rack to separate stone sizes. The typical load is estimated at 4100kg and falls about 1m above the screen. My velocity at impact works out to about 4.4m/s just before impact (determined by SQRT(2 x 9.81m/s^2 x Height of fall). From this my impulse works out to (mass x change in velocity) 18,040 kg-m/s How do I determine the Impact Force? I don't know the deflection, or the change in time to bring the load to rest - these are both unkown. Any pointers?