高一物理必修二 第五章圆周运动(动画版).ppt

Attitude is just as important as ability! Attitude is just as important as ability! 匀速圆周运动匀速圆周运动圆周运动特征:质点的轨迹是圆周、具有周期性 Attitude is just as important as ability! 运动轨迹是圆周的运动叫圆周运动 Attitude is just as important as ability! 思考与讨论( P 13) 自行车的轮盘,飞轮,后轮中的质点都在做圆周运动。哪些点运动得更快些? Attitude is just as important as ability! 我们曾经用速度这个概念来描述物体做直线运动时的快慢,那么我们能否继续用这个概念来描述圆周运动的快慢呢?如果能,该怎样定义? 下面就请同学们自主学习课本第 14页上有关线速度的内容: 一. 线速度 Attitude is just as important as ability! 阅读提纲①线速度的物理意义; ②线速度的定义(和直线运动中速度定义的比较) ③线速度的定义式; ④线速度的瞬时性; ⑤线速度的方向; ⑥匀速圆周运动的“匀速”同“匀速直线运动”的“匀速”一样吗? Attitude is just as important as ability! 质点沿圆周通过的弧长与所用时间的比值(比值定义法) 大小: lvt ???定义: 方向: 沿质点所在圆弧处的切线方向单位: / m s 线速度 v物理意义: 描述质点沿圆周运动的快慢。(是弧长,非位移) lvt ??? Attitude is just as important as ability! v匀速圆周运动是变速运动! 速率不变是线速度大小不变的运动! vv o Attitude is just as important as ability! ②同一根指针上不同的点,运动是否有共性? ①根据线速度的定义,请你比较钟表指针中点和端点线速度的大小。这就需要我们去思考:描述圆周运动的快慢, 除了用线速度外,还有没有其他方法? Attitude is just as important as ability! 阅读提纲①角速度的物理意义; ②角速度的定义; ③角速度的定义式。