只需告诉我怎么得出的)!A crash test dummy in a test facility moves on a rolling sled at +2.0 m/s.The rolling sled strikes a rubber barrier and shortly afterward is rolling backward at -1.8 m/s.When the crash test dummy in the sled strikes
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![只需告诉我怎么得出的)!A crash test dummy in a test facility moves on a rolling sled at +2.0 m/s.The rolling sled strikes a rubber barrier and shortly afterward is rolling backward at -1.8 m/s.When the crash test dummy in the sled strikes](/uploads/image/z/7128059-59-9.jpg?t=%E5%8F%AA%E9%9C%80%E5%91%8A%E8%AF%89%E6%88%91%E6%80%8E%E4%B9%88%E5%BE%97%E5%87%BA%E7%9A%84%EF%BC%89%21A+crash+test+dummy+in+a+test+facility+moves+on+a+rolling+sled+at+%2B2.0+m%2Fs.The+rolling+sled+strikes+a+rubber+barrier+and+shortly+afterward+is+rolling+backward+at+-1.8+m%2Fs.When+the+crash+test+dummy+in+the+sled+strikes)
只需告诉我怎么得出的)!A crash test dummy in a test facility moves on a rolling sled at +2.0 m/s.The rolling sled strikes a rubber barrier and shortly afterward is rolling backward at -1.8 m/s.When the crash test dummy in the sled strikes
只需告诉我怎么得出的)!
A crash test dummy in a test facility moves on a rolling sled at +2.0 m/s.The rolling sled strikes a rubber barrier and shortly afterward is rolling backward at -1.8 m/s.When the crash test dummy in the sled strikes the rubber barrier,it experiences?
negative acceleration
为什么是负加速度?
只需告诉我怎么得出的)!A crash test dummy in a test facility moves on a rolling sled at +2.0 m/s.The rolling sled strikes a rubber barrier and shortly afterward is rolling backward at -1.8 m/s.When the crash test dummy in the sled strikes
这道题目其实就是是问,一个物体他以正速度碰撞另一物体后速度变为负.问他碰撞中他经历了什么.那就是负加速度使它速度变为负啦~这样行么
?告诉我是英语的还是语文的好么?这样怎么回答啊我~!!
因为原速度是+2.0m/s
撞到橡胶围栏上,速度变为-1.8m/s
速度方向和大小都改变
由Vt-V0=at
Vt=-1.8
V0=+2.0
at=-3.8
t>0
得到a<0