题目

地球赤道上有一物体随地球的自转而做圆周运动，所受的向心力为F1，向心加速度为a1,线速度为v1,角速度为ω1;绕地球表面附近做圆周运动的人造卫星受的向心力为F2，向心加速度为a2，线速度为v2,角速度为ω2;地球同步卫星所受的向心力为F3，向心加速度为a3,线速度为v3，角速度为ω3.地球表面重力加速度为g，第一宇宙速度为v，假设三者质量相等.则（    ） A.F1=F2＞F3                  B.a1=a2=g＞a3C.v1=v2=v＞v3              D.ω1=ω3＜ω2 I'M GOING TO BE FAMOUS!I thought I was in big trouble, for sure.But Mr. Dayton wanted to hear my side of the story. So I told him about trying to break a world record by eating seventeen bananas in less than two minutes. And I told him about my bets with Kerry and John. And I even told him about the Positive Brain Approach (积极思维法) that Ben and I were using. I told him about Murray, and how mad it made me that everybody was telling me I couldn't break a world record and that it was stupid that I would even try. I told Mr. Dayton everything. Then I stood there like I'd been caught with my hand stuck in the cookie jar. And I waited.Mr. Dayton looked at me really hard and twitched his mustache again. “Arlo," he said, “I don't see anything wrong with trying to break a world record." I think I probably let out a big sigh then. “But," Mr. Dayton said, “I can't help wondering why you really want to do it."That seemed a plain fact to me: I want to do it so I can be in the Guinness Book of World Records. It'll be Arlo Moore, world-famous banana-eater extraordinaire (卓越). I'll be on TV. I'll be in the movies. I'll win my bets. “Arlo," Mr. Dayton said." “Yes sir, Mr. Dayton,” I replied. "Think about why you are doing this. OK?" That sounded easy enough. I've already thought about it enough to turn an apple brown. “And don't let this interfere (干扰) with your schoolwork," he added.That didn't sound easy. But I figured I could manage to pay better attention in class. And I couldn't have been so determined (有决心的) if I hadn't talked to Mr. Dayton.【1】What did Arlo try to do to break a world record?A.He tried to eat seventeen bananas in less than two hours.B.He tried to eat seventeen bananas in less than two minutes.C.He tried to eat seventy bananas in less than two hours.D.He tried to eat seventy bananas in less than two minutes.【2】Who seems to be helping Arlo with his goal?A.Kerry.B.John.C.Ben.D.Murray.【3】Which of the following statements is true?A.Arlo was a naughty boy and always got into trouble.B.Arlo couldn't get on with classmates and had no friends.C.Mr. Dayton understood Arlo but expected more from him.D.It was impossible for Arlo to pay better attention in class.【4】What is most likely to happen next in the story?A.Arlo will choose a completely different record to try to break.B.Mr. Dayton will decide to try to break a record of his own.C.All the boys will help Arlo as he tries to break the record.D.Arlo will work on ways to break the banana-eating record.