Question

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Answer 1

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½â´ð ½â£º${v}_{1}^{\;}=216km/h=60m/s$
${v}_{2}^{\;}=90km/h=25m/s$
µÚÒ»½×¶Î¼õËÙʱ¼ä£º${t}_{1}^{\;}=\frac{{v}_{1}^{\;}-{v}_{2}^{\;}}{{a}_{1}^{\;}}=\frac{60-25}{0.5}s=70s$
µÚ¶þ½×¶Î¼õËÙʱ¼ä${t}_{2}^{\;}=\frac{{v}_{2}^{\;}}{{a}_{2}^{\;}}=\frac{25}{0.25}s=100s$
${t}_{1}^{\;}+{t}_{2}^{\;}£¼3min$£¬ËùÒÔ3minÄÚ¶¯³µÒÑÍ£Ö¹Ô˶¯
3minÄÚͨ¹ýµÄλÒÆ
$x=\frac{{v}_{1}^{2}-{v}_{2}^{2}}{2{a}_{1}^{\;}}+\frac{{v}_{2}^{2}}{2{a}_{2}^{\;}}=\frac{6{0}_{\;}^{2}-2{5}_{\;}^{2}}{2¡Á0.5}+\frac{2{5}_{\;}^{2}}{2¡Á0.25}$=4225m
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