You are designing a high speed elevator for a new skyscraper. The elevator will has a mass limit of 2400 kg. For passenger comfort, you choose the maximum ascent speed to be 18.0 m/s, the maximum descent speed to be 10.0 m/s, and the maximum acceleration magnitude to be 4.60 m/s squared. Ignore friction. What is the minimum time it will take the elevator to ascend from the lobby to the observation deck, a vertical displacement of 640 m?