题目

某人造卫星运动的轨道可近似看作是以地心为中心的圆．由于阻力作用，人造卫星到地心的距离从r1慢慢变到r2，用EKl、EK2分别表示卫星在这两个轨道上的动能，则（              ）                                                A． r1＜r2，EK1＜EK2    B． r1＞r2，EK1＜EK2    C． r1＜r2，EK1＞Ek2     D．       r1＞r2，EK1＞EK2                                                                The Maine School LIBRARYOPENING HOURS THURSDAY 09:00-17:00MONDAY 09:00-17:00 FRIDAY 09:00-17:00TUESDAY 09:00-17:00 SATURDAY 09:00-17:00WEDNESDAY 09:00-17:00 SUNDAY CLOSEDLIBRARY RULESAll students must have a library card.Computers are for schoolwork only.No food or drink in the library.No running or shouting in the library.Mobile phones must be turned off.Students can borrow 3 books at one time.【1】You can read books ________ in the Maine School Library.A.from 9 a.m. to 5 p.m. on TuesdayB.from 9 a.m. to 12 p.m. on SundayC.from 8 a.m. to 2 p.m. Friday【2】You must have ________ to borrow books from the Maine School Library.A.an ID cardB.a library cardC.a student ID card【3】Which of the following is TRUE according to the rules of the Maine School Library?A.You can borrow 3 books and have some Coca Cola at the library.B.You can use the computer of the library to chat with your friends.C.You can take a mobile phone and some pens to the library.