Question

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Answer 1

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ÓÉͼÏó¿ÉÖª£¬¼×³µÖƶ¯Ê±¼ä${t}_{1}^{\;}=3s$ÄÚ£¬ÒÒ³µ±£³ÖÔÈËÙÐÐÊ»£¬ÐÐÊ»¾àÀë${x}_{1}^{\;}={v}_{0}^{\;}{t}_{1}^{\;}=30¡Á3=90m$
ÓÉÓÚ${x}_{1}^{\;}£¼{x}_{0}^{\;}$£¬¼×¡¢ÒÒÁ½³µÔÚ0¡«3sÄÚ²»ÄÜÏàײ
${t}_{1}^{\;}=3s$Ä©¼×³µËÙ¶ÈΪ${v}_{1}^{\;}={v}_{0}^{\;}+{a}_{1}^{\;}{t}_{1}^{\;}=30-10¡Á3=0$
Éè¼×³µÖƶ¯${t}_{1}^{\;}=3s$ºó£¬ÔÙ¾­¹ý${t}_{2}^{\;}$ʱ¼ä¼×¡¢ÒÒÁ½³µËÙ¶ÈÏàµÈ£¬¼´£º${a}_{2}^{\;}{t}_{2}^{\;}={v}_{0}^{\;}+{a}_{3}^{\;}{t}_{2}^{\;}$
´úÈëÊý¾Ý£º$5{t}_{2}^{\;}=30-5{t}_{2}^{\;}$
¿ÉµÃ${t}_{2}^{\;}=3s$
Á½³µËÙ¶ÈÏàµÈʱ£¬¼×³µÎ»ÒÆ${x}_{¼×}^{\;}=\frac{{v}_{0}^{\;}}{2}{t}_{1}^{\;}+\frac{1}{2}{a}_{2}^{\;}{t}_{2}^{2}$=$\frac{30}{2}¡Á3+\frac{1}{2}¡Á5¡Á{3}_{\;}^{2}=67.5m$
ÒÒ³µÎ»ÒÆ${x}_{ÒÒ}^{\;}={v}_{0}^{\;}{t}_{1}^{\;}+{v}_{0}^{\;}{t}_{2}^{\;}+\frac{1}{2}{a}_{3}^{\;}{t}_{2}^{2}$=$30¡Á3+30¡Á3+\frac{1}{2}¡Á£¨-5£©¡Á{3}_{\;}^{2}=157.5m$
ÓÉÓÚ${x}_{¼×}^{\;}+{x}_{0}^{\;}=167.5£¾{x}_{ÒÒ}^{\;}$£¬¹ÊÁ½³µ²»»áÏàײ
¾­¹ý${t}_{2}^{\;}=3s$£¬¼×¡¢ÒÒÁ½³µËÙ¶ÈÏàµÈ£¬´ËʱÁ½³µ¼ä¾à×î½ü
×î½ü¾àÀë$¡÷x={x}_{¼×}^{\;}+{x}_{0}^{\;}-{x}_{ÒÒ}^{\;}=167.5-157.5=10m$
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