题目

如图，一半圆形碗的边缘上装有一定滑轮，滑轮两边通过一不可伸长的轻质细线挂着两个小物体，质量分别为m1、m2, m1＞m2。现让m1从靠近定滑轮处由静止开始沿碗内壁下滑。设碗固定不动，其内壁光滑、半径为R。则m1滑到碗最低点的速度为：（     ）A．               B． C．               D． The number of deaths from heart disease will be reduced greatly if people _____ to eat more fruit and vegetables. A. persuade      B. will persuade      C. be persuaded      D. are persuaded