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多选题
速度的大小和方向都不断改变,但加速度的大小和方向都不变的运动是( ).
A
匀速圆周运动
B
自由落体运动
C
平抛运动
D
竖直上抛运动
参考答案
参考解析
解析:
在自由落体运动中,速度方向不变,速度大小不断改变;竖直上抛运动时,速度大小不断改变,但在上升和下落时速度的方向不变.匀速圆周运动速度方向时刻变化,但速度大小不变.可见,上面三种运动都不满足速度大小和方向都不断改变的条件,.平抛运动速度的大小和方向不断变化,而加速度为重力加速度g,大小、方向都不变.
在自由落体运动中,速度方向不变,速度大小不断改变;竖直上抛运动时,速度大小不断改变,但在上升和下落时速度的方向不变.匀速圆周运动速度方向时刻变化,但速度大小不变.可见,上面三种运动都不满足速度大小和方向都不断改变的条件,.平抛运动速度的大小和方向不断变化,而加速度为重力加速度g,大小、方向都不变.
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