When an elevator starts, the acceleration is 2 m / S2, when braking, the acceleration is 1 m / S2, and the building height is 64 M (1) If the maximum speed is 6 m / s, what is the shortest time for the elevator to reach the top of the building? (2) If the elevator first accelerates, then rises at a constant speed, and finally decelerates, the total time is 16 seconds?

When an elevator starts, the acceleration is 2 m / S2, when braking, the acceleration is 1 m / S2, and the building height is 64 M (1) If the maximum speed is 6 m / s, what is the shortest time for the elevator to reach the top of the building? (2) If the elevator first accelerates, then rises at a constant speed, and finally decelerates, the total time is 16 seconds?

(1) If the maximum speed of ascent is 6 m / s, the acceleration displacement is 6 ^ 2 / (2 * 2) = 9 m, the deceleration displacement is 6 ^ 2 / (2 * 1) = 18 m, so the time of uniform velocity is (64-18-9) / 6 = 37 / 6 s, so the time is 6 / 2 + 6 / 1 + 37 / 6 = 91 / 6 s; (2) if the maximum speed of ascent is V, the time of uniform velocity is 16-v / 1-V / 2 = 16-3v / 2, so