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
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