Acceleration = (change in speed) / (time for the change)
Change in speed = (speed at the end) - (speed at the beginning)
Change in speed = (zero) - (35 mi/hr)
Change in speed = -35 mi/hr
Acceleration = (-35 mi/hr) / (0.5 sec)
Acceleration = -70 mi / hr-sec
That's (-102 and 2/3) feet/sec² . . . about -3.2 Gs !
It's also about -31.3 meter/sec² . (rounded)
