只需告诉我怎么得出的)!A crash test dummy in a test facility moves on a
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?