题目

设想宇航员完成了对火星表面的科学考察任务，乘坐返回舱返回围绕火星做圆周运动的轨道舱，如图所示。为了安全，返回舱与轨道舱对接时，必须具有相同的速度。已知返回舱返回过程中需克服火星的引力做功，返回舱与人的总质量为m，火星表面的重力加速度为g ，火星的半径为R，轨道舱到火星中心的距离为r，不计火星表面大气对返回舱的阻力和火星自转的影响，则该宇航员乘坐的返回舱至少需要获得多少能量才能返回轨道舱？   阅读理解 根据材料内容选择最佳答案，并将其标号填入提前括号内。 (1) All the information about the writer must be included except his/her _________． [　　] A． school name B． e-mail address C． year of birth D． telephone number (2) What is required for the articles wanted according to the passage? [　　] A． They must be fully created by the writers themselves． B． They must be typed in single space and on both sides． C． They must be provided with photos and descriptions． D． They must be sent with the copies of texts and pictures． (3) According to the passage, you can send your articles _________． [　　] A． within 3 weeks B． ail summer C． ail the year round D． during the whole term (4) How many ways can you find in the passage to contact School Life? [　　] A． 1． B． 2． C． 3． D． 4． (5) Who do you think will write articles for School Life? [　　] A． Students who are interested in writing． B． Teachers who love writing and taking photos． C． Parents who wish their kids to be popular writers． D． Readers who had a happy time in their childhood．