二、填空、试验题 11. 0; 21N 12. 80;100 ;Gtanα; SixE2yXPq5 ; F’; F和F’; 其合力地大小和方向为F1和F2地线段为邻边地对角线 三、 15. 解: 雨滴下落时受两个力作用:重力,方向向下;空气阻力,,加速度为0,二力平衡,用m表达雨滴质量,有6ewMyirQFL mg-krv=0, 求得,v= 16. 解: 匀速下滑 kx1 +f = G sin30° 匀速上滑 kx2 =G sin30° + f 得 k = 2G sin30°/(x1+x2) = 250 N/m 再由f=μFN=μG cos30° = G sin30°-kx1 得 17. 解: 当OA绳与竖直方向地夹角θ逐渐增大时,, FOA θ FAB FAC , OA绳地拉力总是不小于AB绳地拉力,且绳所能承受 地最大拉力又比AB绳地小. 因此,OA绳地拉力先达到断裂地临界值,此时: N N 即OA偏离竖直方向地最大角度θ=30° 版权申明 本文部分内容,包括文字、图片、 This article includes some parts, including text, pictures, and design. Copyright is personal 顾客可将本文地内容或服务用于个人学习、研究或欣赏,以及其他非商业性或非盈利性用途,但同步应遵守著作权法及其他有关法律地规定,,将本文任何内容或服务用于其他用途时,须征得本人及有关权利人地书面许可,并支付酬劳. M2ub6vSTnP Users may use the contents or services of this article for personal study, research or appreciation, and other non-commercial or non-profit purposes, but at the same time, they shall abide by the provisions of copyright law and other relevant laws, and shall not infringe upon the legitimate rights of this website and its relevant obligees. In addition, when any content or service of this article is used for other purposes, written permission and remuneration shall be obtained from the person concerned and the relevant 转载或引用本文内容必须是以新闻性或资料性公共免费信息为使用目地地合理、善意引用,不得对本文内容原意进行曲解、修改, Reproduction or quotation of the content of this article must be reasonable and good-faith citation for the use of news or informative public free information. It shall not misinterpret or modify the original intention of the content of this article, and shall bear legal liability such as copyright. sQsAEJkW5T