【2017年整理】P2.4专题1匀变速直线运动规律推论及其应用.ppt

13．如图所示，传送带的水平部分长为L，传送速率为v，在其左端无初速释放一小木块，若木块与传送带间的动摩擦因数为μ，则木块从左端运动到右端的时间不可能是( ) B Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 【解析】当在传送带的左端无初速释放一木块后，木块在传送带上的运动有两种可能，一种可能是木块一直加速其时间最短，则其运动时间可以表示为C、D两种形式；另一种可能是木块先加速，当达到与传送带相同速度后，摩擦力消失，木块再做匀速运动到右端，此时其运动时间是选项A，所以不可能的就是B. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. AD Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. D Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 16．一间新房即将建成时要封顶，考虑到下雨时让落至房顶的雨滴能最快地淌离房顶，要设计好房顶的坡度．设雨滴沿房顶无初速度的下淌(忽略雨滴与房顶的摩擦，且整个房顶底边的宽度相同)．那么，图中所示的四种情况中符合要求的是( ) C 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. A 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. 18．带式传送机是在一定 的线路上连续输送物料 的搬运机械，又称连续输送机．如图所示，一条足够长的浅色水平传送带自左向右匀速运行．现将一个木炭包无初速度地放在传送带上，木炭包在传送带上将会留下一段黑色的径迹．下列说法正确的是( ) A．黑色的径迹将出在木炭包的左侧 B．木炭包的质量越大，径迹的长度越短 C．木炭包与传送带间动摩擦因数越大，径迹的长度越短 D．传送带运动的速度越大，径迹的长度越短 C 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. A Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 20.一物体做匀加速直线运动，经A、B、C三点，已知AB＝BC，AB段平均速度为20 m/s，BC段平均速度为30 m/s，则可求得( ) A．初速度vA B．末速度vC C．AC段的平均速度 D．物体运动的