英語翻譯
A rocket designed to place small payloads into orbit is carried to an altitude of 12.0km above sea level by a converted airliner.When the airliner is flying in a straight line at a constant speed of 850km/h ,the rocket is dropped.After the drop,the airliner maintains the same altitude and speed and continues to fly in a straight line.The rocket falls for a brief time,after which its rocket motor turns on.Once its rocket motor is on,the combined effects of thrust and gravity give the rocket a constant acceleration of magnitude 3.00g directed at an angle of 30.0 above the horizontal.For reasons of safety,the rocket should be at least 1.00km in front of the airliner when it climbs through the airliner's altitude.
Your job is to determine the minimum time that the rocket must fall before its engine starts.You can ignore air resistance.