关于加速的的简单英文物理题At a certain instant a moving object comes tomomentary rest.Is it accelerating at that moment?1.No2.Acceleration is unrelated to speed,so thequestion does not make sense.3.Yes4.There is no way to tell from the i
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关于加速的的简单英文物理题At a certain instant a moving object comes tomomentary rest.Is it accelerating at that moment?1.No2.Acceleration is unrelated to speed,so thequestion does not make sense.3.Yes4.There is no way to tell from the i
关于加速的的简单英文物理题
At a certain instant a moving object comes to
momentary rest.
Is it accelerating at that moment?
1.No
2.Acceleration is unrelated to speed,so the
question does not make sense.
3.Yes
4.There is no way to tell from the informa-
tion given.
关于加速的的简单英文物理题At a certain instant a moving object comes tomomentary rest.Is it accelerating at that moment?1.No2.Acceleration is unrelated to speed,so thequestion does not make sense.3.Yes4.There is no way to tell from the i
翻译:
一个移动的物体在通过一定距离之后,暂时停止了运动.请问在这个时刻,它是否在加速?
1.否.
2.加速度和速度无关,所以这个问题没有意义.
3.是.
4.无法得出任何结论.
根据牛顿第二定律,F=ma,加速度a的大小和方向与速度无关,而和施加在物体上的合外力以及物体本身质量有关.运动物体由运动状态转变为静止,那么之前一定是在做受不为0的外力的减速运动.但是,假如在物体速度减到0的时刻,物体所受合外力变成了0,那么它就不在做加速运动.
但是,笼统地说“加速度与速度无关(Acceleration is unrelated to speed)”,我认为是错误的,因为加速度虽然不由速度决定,但它反过来可以改变速度,加速度与时间的乘积就是速度的增量.
所以选4.