Set xf-xo to 200 meters, vo to 140 mi/h (first switch to miles & hours with Ctrl-I and Ctrl-H), and vf to 70 mi/h. Switch back to meters & seconds (Ctrl-M and Ctrl-S), to see acceleration of -7.344295 m/ss (a bit less than 1g). Hit enter in the ao textbox to make ao an independent variable, hit enter in the vo textbox to refresh its status as an independent variable, and then reset vf to 0. Viola: Stopping distance is 266 meters or about 1/6 mi.