你是一位物理老师，需要给学生进校这个题目的讲解，麻烦给出一个讲解视频，逐一对每个选项进行分析，给出正确的答案。---1. (多选) 轮渡是过去人们过河经常采用的一种交通方式。如图是摆渡船轮渡的情景；已知船在静水中的速度为 v₁=10m/s, 当船在 A 处，船头与上游河岸夹角 θ = 53° 过河，经过一段时间正好到达正对岸 B 处。已知河宽 d = 200m，船在静水中速度大小不变，水流的速度不变，则下列说法中正确的（ ） **Chart/Diagram Description:** Type: Diagram illustrating a boat crossing a river. Main Elements: - Two parallel horizontal lines representing the river banks. - Point A on the lower bank. - Point B on the upper bank, directly opposite point A, indicated by a vertical dashed line connecting A and B. - Three horizontal arrows pointing to the right, labeled "水流" (Water flow), indicating the direction of the current. "上游" (Upstream) is labeled to the left, implying the current flows downstream to the right. - River width is the vertical distance between the banks, labeled as d = 200m by the dashed line AB. - A vector labeled v₁ originates from A, pointing towards the upper bank and slightly to the left (upstream). This vector represents the boat's velocity relative to the water. - An angle labeled θ is shown between the vector v₁ and the vertical dashed line (representing the direction directly across the river). The value θ = 53° is given in the text. **Options:** A. 此时船的渡河时间为 20s B. 此时河中水流速度为 8m/s C. 若船选择以最短时间过河，最短的渡河时间为 20s D. 若水流速度突然增大变为 15m/s, 则小船重新调整方向也无法到达正对岸 B 处