5. Two people fell down, one onto hard cement and one onto softer grass. Both people had a mass of 100 kg and were moving at 4 m/s as they fell. The person who hit the hard cement came to a complete stop very quickly, in .01 seconds. The person who fell onto the softer grass also came to a complete stop, but they did so more slowly, 0.5 seconds. What force did each of them experience when they came to a stop?