题目

在国庆阅兵演习中，某直升机在地面上空某高度A位置处于静止状态待命，现接上级命令，要求该直升机10时58分20秒由静止状态沿水平方向做匀加速直线运动，经过AB段加速后，进入BC段的匀速受阅区，11时准时通过C位置．已知xAB＝5 km，xBC＝10 km.问： (1)直升机在BC段的速度大小是多少？ (2)直升机在AB段做匀加速直线运动时的加速度大小是多少？单词拼写Do you like reading stories? Almost everyone does. Good stories are fun to read. Good stories let you share eadventures. They make you lwhen something funny was said or done. They make you shiver(颤抖) when something is f. They make you glad when the ending turns out to be h.Good stories help you to learn about other times, other people and other p. They may even help you to learn more about y.What kof good stories do you know? There are stories about make-believe(虚构的) people, such as those about DHolmes or Cinderella. There are also stories about fpeople, such as those about the Wright brothers and Abraham Lincoln. There are stories about a, such as The Lion King and The Three Little Pigs.