A spaceship ferrying workers to moon base i takes a straight-line path from the earth to the moon, a distance of 384000 km. suppose it accelerates at an acceleration 19.9 m/s2 for the first time interval 14.7 min of the trip, then travels at constant speed until the last time interval 14.7 min , when it accelerates at − 19.9 m/s2 , just coming to rest as it reaches the moon. part a what is the maximum speed attained?