在下列情況中,求問：相同時間內(nèi)物體的平均速度小于平均速率的選項是（）
A.物體沿+x移動,不掉頭
B.物體沿-x移動,不掉頭
C.物體沿+x移動,然后掉頭
D.上述都不對
選C.因為平均速度=位移/時間,平均速率=路程/時間.既然時間相同,那么不掉頭的運(yùn)動其|位移|=路程,而掉頭運(yùn)動,|位移|<路程,所以|平均速度|<平均速率.
英語翻譯
英語翻譯
Under which of the following conditions is the magnitude of the average velocity of a particle moving in one dimension smaller than the average speed over some time interval?A.A particle moves in the +x direction without reversing.B.A particle moves in the -x direction without reversing.C.A particle moves in the + x direction and then reverses the direction of its motion.D.There are no conditions for which this is true.
Under which of the following conditions is the magnitude of the average velocity of a particle moving in one dimension smaller than the average speed over some time interval?A.A particle moves in the +x direction without reversing.B.A particle moves in the -x direction without reversing.C.A particle moves in the + x direction and then reverses the direction of its motion.D.There are no conditions for which this is true.
英語人氣：475 ℃時間：2019-10-19 16:00:22
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