An airplane is accelerated straight up to 20m / (s ^ 2) by six identical engines when one of the engines fails. What is the airplane acceleration after the engine failure? Consider g = 9.8m / (s ^ 2) Select one: a 12.3m / (s ^ 2) b . 15m / (s ^ 2) c . 15.6m / (s ^ 2) O d. 16m / (s ^ 2)