一、认准条件条件是解题的依据,解题时首先要洞察条件,并根据题中条件合理选用物理公式,切忌盲目套用.小球能在半径为R的粗糙环状细管内滑动,细管被竖直放置,设在图1所示的位置给小球沿切线方向竖直向上的初速度v0,小球恰能在细管内滑动一周而停止,则小球受到的摩擦力所做的功 First, look for conditional conditions is the basis for problem solving, the solution to the problem, first of all to gain insight into the conditions, and according to the conditions of the problem, the rational selection of physical formulas, avoid blindly applied. The ball can slide in a rough ring-shaped tube with a radius of R, fine The tube is placed vertically, and the initial velocity v0 in the tangential direction of the ball is set at the position shown in Fig. 1. The ball can be stopped by sliding in the tube for one week and the ball is subjected to friction. Work