Set xf-xo to 28 meters, vo to 0, and ao to 9.8 m/ss (the acceleration due to gravity). This gives impact velocity of 23.4 meters/second after a 2.4 second fall. Next Set xf-xo to 0.5 meters, vo to 23.4 m/s (impact velocity), and vf=0 (velocity after the crunching stopped). Deceleration was 547m/ss or >50 g's! The crunch only lasted for .04 seconds.