(16分)一辆汽车沿平直公路从甲站开往乙站，启动加速度为2 m/s 2 ，加速行驶5 s后匀速行驶2 min，然后刹车 一辆汽车沿平直公路从甲站开往乙站，启动加速度为2m/s&su...
\u4e00\u8f86\u6c7d\u8f66\u6cbf\u5e73\u76f4\u516c\u8def\u4ece\u7532\u7ad9\u51fa\u53d1\u5f00\u5f80\u4e59\u7ad9\uff0c\u8d77\u52a8\u52a0\u901f\u5ea6\u4e3a2m/s2\uff0c\u52a0\u901f\u884c\u9a765\u79d2\uff0c\u540e\u5300\u901f\u884c\u9a762\u5206\u949f\uff0c\u7136\u540e\u5239\u8f66\u505a\uff081\uff09\u6c7d\u8f66\u505a\u5300\u52a0\u901f\u8fd0\u52a8\u65f6\u7684\u52a0\u901f\u5ea6a=2m/s2\uff0c\u52a0\u901f\u8fd0\u52a8\u7684\u65f6\u95f4\u4e3a5s\uff0c\u5219\u6c7d\u8f66\u5728\u5300\u52a0\u901f\u8fc7\u7a0b\u4e2d\u7684\u4f4d\u79fbx1\uff1d12at2\uff1d12\u00d72\u00d752m\uff1d25m\u6839\u636e\u901f\u5ea6\u65f6\u95f4\u5173\u7cfb\u53ef\u77e5\uff0c\u52a0\u901f5s\u540e\u6c7d\u8f66\u7684\u901f\u5ea6v=at=2\u00d75m/s=10m/s\uff0c\u5219\u6c7d\u8f66\u5728\u5300\u901f\u8fd0\u52a82\u5206\u949f\u65f6\u95f4\u5185\u7684\u4f4d\u79fbx2=vt=10\u00d7120m=1200m\u6c7d\u8f66\u505a\u5300\u51cf\u901f\u8fd0\u52a8\u7684\u4f4d\u79fbx3=50m\u6240\u4ee5\u7532\u4e59\u4e24\u7ad9\u95f4\u7684\u8ddd\u79bbx=x1+x2+x3=25+1200+50m=1275m\uff082\uff09\u6c7d\u8f66\u505a\u5300\u51cf\u901f\u8fd0\u52a8\u7684\u521d\u901f\u5ea6v0=10m/s\uff0c\u672b\u901f\u5ea6v=0\uff0c\u4ea7\u751f\u7684\u4f4d\u79fbx3=50m\u5219\u6839\u636e\u5300\u53d8\u901f\u76f4\u7ebf\u8fd0\u52a8\u7684\u5e73\u5747\u901f\u5ea6\u516c\u5f0f\u77e5\uff0c\u5300\u51cf\u901f\u8fd0\u52a8\u8fc7\u7a0b\u4e2d\u7684\u5e73\u5747\u901f\u5ea6.v3\uff1dv+v02\uff1d0+102m/s\uff1d5m/s\u6240\u4ee5\u5300\u51cf\u901f\u8fd0\u52a8\u8fc7\u7a0b\u65f6\u95f4t3\uff1dx3.v3\uff1d505s\uff1d10s\u6240\u4ee5\u6c7d\u8f66\u4ece\u7532\u81f3\u4e59\u6240\u7528\u65f6\u95f4t=t1+t2+t3=5+120+10s=135s\u5219\u6c7d\u8f66\u4ece\u7532\u5230\u4e59\u7684\u5e73\u5747\u901f\u5ea6.v\uff1dxt\uff1d1275135m/s\u22489.4m/s\u7b54\uff1a\uff081\uff09\u7532\u4e59\u4e24\u7ad9\u4e4b\u95f4\u7684\u8ddd\u79bb\u4e3a1275m\uff0e\uff082\uff09\u6c7d\u8f66\u4ece\u7532\u7ad9\u5230\u4e59\u7ad9\u7684\u5e73\u5747\u901f\u5ea6\u4e3a9.4m/s\uff0e
\u52a0\u901f\u884c\u9a765s
s1=(1/2)a*5^2=25 m
v=2*5 m/s=10 m/s
\u5300\u901f\u884c\u9a762min
s2=10*120 m=1200 m
\u6ed1\u884c50m,
50=(1/2)10t
t=10 s
\u4ece\u7532\u7ad9\u5230\u4e59\u7ad9\u7684\u5e73\u5747\u901f\u5ea6(25+1200+50)/(5+120+10) m/s=
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