§1-3-2 点的三面投影及投影规律 §1-4 直线的投影 §1-5 平面的投影

History and Policy in the sixties Reading 1. Spaceflight and the Myth of Presidential Leadership?\Chapters 2&3 2.“ The Heavens and the earth” Chapters 11-22 3.“ Beyond Horizons” Chapter3 Strategic themes The use of the Space Program as a political tool to show the superiority of the

Who is in the Space Enterprise and what are their roles? Reading A. US National Space Policy, http://www.whitehouse.gov/wh/eop/osTp/htmL/ostpHomehtml B.DodSpacePolicyhttp://www.c3i.osd.mil/org/c3is/spacepol/index.html C.Nrohomepagehttp://www.nro.mil D.Nasahomepagehttp://www.nasa.gov/enterprises.html

2-3图示翻罐笼由滚轮A、B支承,已知翻罐笼连同煤车共重 W=3kN,a=30°,B=45°。求滚轮A、B所承受的压力。有人认为 F=Wcos,FB=Wcosβ,对不对,为什么? 解:翻罐笼受力如图所示。建立图 示坐标系,列平衡方程 联解方程,得 F155N

一、填空题(满分15分) 1.已知P(B)=0.3,P(AB)=0.7,且A与B相互独立,则P(A)= 学 2.设随机变量X服从参数为二项分布,且P{X=0}=,则p= 号: 3.设X~N(3,02),且PX<0}=0.1,则P{3