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物理新课标必须修读1,4—7.ppt

发布:2017-03-25约7.8千字共50页下载文档
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答案:B Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 用绳AO、BO悬挂一重物,BO水平,O为半圆形支架的圆心,悬点A和B在支架上.悬点A固定不动,将悬点B从图(a)所示位置逐渐移动到C点的过程中,分析OA绳和OB绳中的拉力变化情况. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 解析:在支架上选取三个点B1、B2、B3,当悬点B分别移动到B1、B2、B3各点时,AO、BO中的拉力分别为TA1、TA2、TA3和TB1、TB2、TB3,如图(b)所示,从图中可以直观地看出,TA逐渐变小,且方向不变;而TB先变小,后变大,且方向不断改变;当TB与TA垂直时,TB最小. 点评:相对解析法而言,作图法比较直观,本题是定性比较问题,选用作图法较为方便,平行四边形是由两个全等的三角形构成,因而在分析动态变化问题时选用三角形定则更为方便. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. (安徽阜阳一中09-10学年高一上学期期末)在固定于地面的斜面上垂直安放了一个挡板,截面为圆的柱状物体甲放在斜面上,半径与甲相等的光滑圆球乙被夹在甲与挡板之间,没有与斜面接触而处于静止状态,如图所示.现在从球心O1处对甲施加一平行于斜面向下的力F,使甲沿着斜面方向极其缓慢地移动,直至甲与挡板接触为止.设乙对挡板的压力为F1,甲对斜面的压力为F2,在此过程中 (  ) Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. A.F1缓慢增大,F2不变 B.F1缓慢增大,F2缓慢减小 C.F1缓慢减小,F2缓慢增大 D.F1缓慢减小,F2不变 答案:D Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 如图所示,台秤上装有盛水的杯,杯底用细绳系一木质小球,若细线突然断裂,则在小木球上浮到水面的过程中,台秤的示数将 (  ) A.变小 B.变大 C.不变 D.无法判断 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 第四章 牛顿运动定律 人教版物理 7.用牛顿运动定律解决问题(二) Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. ※ ※※ ※ ※※ 知道平衡状态,理解共点力作用下物体的平衡条件 能解决简单的平衡问题 知道超重、失重现象 能用牛顿定律解决有关超重和失重问题 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides
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