The coast-down time y for a car as it drops 10 mph from an initial speed x depends on several factors, such as average drag, tire pressure, and whether the transmission is in neutral. The table gives coast-down time in seconds for a car under standard conditions for selected speeds.
initial speed (mph) coast down time (seconds) intial speed (mph) coast down time(seconds)
30 30 50 18
27 55 16
35 23 60 15
40 20 65 13
45