题目

Watching online open classes of US top universities has become necessary for many young Chinese who find it a shortcut to make their life more meaningful, in addition to learning knowledge and language. Guo Lei, a native of Guangzhou, has become addicted to various open courses after she watched the online video of Justice: What's the right thing to do.The video clip was taken during an open class taught by Michael Sandel, professor of philosophy at Harvard University. Sandel set up a situation in which a high-speed train with a technical problem is running towards five people who are working 5．如图所示，在光滑的水平面上放着一质量为M=4.0kg带弧形槽的木板，AB部分是长度为L=1m的粗糙轨道，BC部分是足够高的光滑弧形槽，BC弧与水平部分AB在B点相切，现有一质量m=2.0kg的物块以初速度v0=5.0m/s从木板左端滑上，已知物块和木板间的摩擦因数μ=0.7，g取10m/s2，求：（Ⅰ）物块从A第一次滑到B时的速度大小；（Ⅱ）物块滑上弧形槽的最大高度h；（Ⅲ）最终物块距B点的距离．