题目

飞机在空中水平匀速飞行，徐冰同学站在水平地面上，用学习过的光学、力学知识，测量飞机的飞行速度，以及声音在空气中的传播速度，当他听到飞机的声音从头顶正上方传来时，发现飞机在他前上方与地面成37º角的方向，如图所示，已知h=2052m，飞机从头顶正上方到达他前上方与地面成37º角的位置时用时6s。求飞机的速度以及声音在空气中的传播速度（直角三角形一个角为37º时，三个边的长度之比为3：4：5）。阅读短文，并选择正确选项。       I am Jack. I am very happy every holiday. I usually go to the library. Sometimes I go to the park. The library is not far. I usually go on foot. I walk straight for fifteen minutes. Then I turn left, the library is on the right. The park is very far. It's near the post office. I often get there by the No. 206 bus, get off at the post office. It's easy to find it. 1. I have a good time every _____________. A. holiday B. weekend 2. I usually go to the _____________ on foot. A. park B. library 3.The library is on _____________. A. the left B. the right 4. I go to the _____________ by bus. A. park B. supermarket 5. The park is near _____________.A. post officeB. library