题干

在平直轨道上行驶的火车,在拐弯前要减到合适的速度才能安全行驶,为了安全拐弯火车正在从180km/h的速度开始做匀减速直线运动,假设安全的拐弯速度为54km/h,要求在50s内恰好到达拐弯处,火车的加速度为多大?

上一题 下一题 0.0难度 选择题 更新时间:2018-03-18 05:03:28

答案(点此获取答案解析)

解:设初速度的方向为正方向,物体做匀减速直线运动

因v0=180km/h=50m/s,vt=54km/h=15m/s

由加速度公式 a=vtv0

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