Question

2£®ÓÖÒ»Äê¹úÇì´ó¼Ù½áÊøÁË£¬ÔÚ´ó¼ÙÆÚ¼ä¹ú¼ÒÈ¡ÏûÁË7×ù¼°ÆäÒÔϵÄС³µµÄÊշѹ«Â·µÄ¹ý··Ñ£¬¸ø×Ô¼ÝÓδøÀ´Á˺ܴóµÄʵ»Ý£¬µ«³µÁ¾µÄÔö¶àÒ²¸ø½»Í¨µÀ·µÄ³©Í¨Ôö¼ÓÁ˺ܴóµÄѹÁ¦£¬Òò´Ë¹ú¼Ò¹æ¶¨ÁËÃâ·Ñ³µÁ¾ÔÚͨ¹ýÊÕ·ÑվʱÔÚרÓõÀÉÏ¿ÉÒÔ²»Í£³µÄûò½»¿¨¶øÖ±½Ó¼õËÙͨ¹ý£®¼ÙÉèÊÕ·ÑÕ¾µÄÇ°¡¢ºó¶¼ÊÇƽֱ´óµÀ£¬´ó¼ÙÆÚ¼ä¹ýÕ¾µÄ³µËÙÒªÇó²»³¬¹ýv_t=6m/s£¬ÊÂÏÈСÆû³µÎ´¼õËٵijµËÙ¾ùΪv₀=30m/s£¬Öƶ¯ºóСÆû³µµÄ¼ÓËٶȵĴóСΪa₁=4m/s²£®ÊÔÎÊ£º
£¨1£©´ó¼ÙÆڼ䣬¼ÝʻԱÖÁÉÙÓ¦ÔÚ¾àÊÕ·ÑÕ¾¶àÔ¶´¦¿ªÊ¼Öƶ¯£¿
£¨2£©¼ÙÉè³µ¹ýÕ¾ºó¼ÝʻԱÁ¢¼´Ê¹³µÒÔa₂=5m/s²µÄ¼ÓËٶȼÓËÙ£¬Ôò³µÒò¼õËٺͼÓËÙ¹ýÕ¾¶øµ¢ÎóµÄʱ¼äÖÁÉÙΪ¶àÉÙ£¿

Answer 1

·ÖÎö £¨1£©¡¢¸ù¾ÝÔȼõËÙÖ±ÏßÔ˶¯Î»ÒÆËٶȹ«Ê½¼´¿ÉÇó½â£®
£¨2£©¸ù¾ÝËÙ¶Èʱ¼ä¹«Ê½·Ö±ðÇó³öÔȼÓËÙºÍÔȼõËÙÔ˶¯µÄʱ¼ä£¬ÒÔ¼°Í¨¹ýËÙ¶ÈλÒƹ«Ê½Çó³öÔȼÓËÙºÍÔȼõËÙÔ˶¯µÄλÒÆ£¬×¥×¡Õâ¶Î×ÜλÒÆÈôÒÔÔ­À´µÄËÙ¶ÈÐÐÊ»Çó³öËùÐèµÄʱ¼ä£¬´Ó¶øµÃ³öµ¢ÎóµÄʱ¼ä£®

½â´ð ½â£ºÉèСÆû³µ³õËٶȷ½ÏòΪÕý·½Ïò
£¨1£©Ð¡Æû³µ½øÈëվ̨ǰ×öÔȼõËÙÖ±ÏßÔ˶¯£¬Éè¾ÝÊÕ·ÑÕ¾x₁´¦¿ªÊ¼Öƶ¯£¬Ôò£º
${v}_{t}^{2}-{v}_{0}^{2}=2{a}_{1}^{\;}{x}_{1}^{\;}$                                                
´úÈëÊý¾Ý½âµÃ£ºx₁=108m                                                     
£¨2£©Ð¡Æû³µÍ¨¹ýÊÕ·ÑÕ¾¾­ÀúÔȼõËÙºÍÔȼÓËÙÁ½¸ö½×¶Î£¬¾­ÀúµÄ×Üʱ¼äΪt₁£¬Ç°ºóÁ½¶ÎµÄλÒÆ·Ö±ðΪx₁ºÍx₂£¬Ôò£º
${t}_{1}^{\;}=\frac{{v}_{t}^{\;}-{v}_{0}^{\;}}{-{a}_{1}^{\;}}+\frac{{v}_{0}^{\;}-{v}_{t}^{\;}}{{a}_{2}^{\;}}$
×Üʱ¼äΪ£ºt₁¨T10.8s                                   
${v}_{0}^{2}-{v}_{t}^{2}=2{a}_{2}^{\;}{x}_{2}^{\;}$
ÔÚ¼ÓËٽ׶Σº½âµÃ£ºx₂=86.4m
Ôò×ÜλÒÆΪ£ºx=x₁+x₂=194.4m                                         
Èô²»¼õËÙËùÐèʱ¼äΪ£º${t}_{2}^{\;}$=$\frac{{x}_{1}^{\;}+{x}_{2}^{\;}}{{v}_{0}^{\;}}$=$\frac{192}{30}=6.48s$
¹Ê£º³µÒò¼õËٺͼÓËÙ¹ýÕ¾¶øµ¢ÎóµÄʱ¼äΪ£º¡÷t=t₁-t₂=4.32 s          
´ð£º£¨1£©´ó¼ÙÆڼ䣬¼ÝʻԱÖÁÉÙÓ¦ÔÚ¾àÊÕ·ÑÕ¾108m´¦¿ªÊ¼Öƶ¯
£¨2£©¼ÙÉè³µ¹ýÕ¾ºó¼ÝʻԱÁ¢¼´Ê¹³µÒÔa₂=5m/s²µÄ¼ÓËٶȼÓËÙ£¬Ôò³µÒò¼õËٺͼÓËÙ¹ýÕ¾¶øµ¢ÎóµÄʱ¼äÖÁÉÙΪ4.32s

µãÆÀ ½â¾ö±¾ÌâµÄ¹Ø¼üÀíÇåСÆû³µÔÚÕû¸ö¹ý³ÌÖеÄÔ˶¯¹æÂÉ£¬½áºÏÔ˶¯Ñ§¹«Ê½Áé»îÇó½â£¬ÖªµÀµ¢ÎóµÄʱ¼äΪʵ¼ÊÔ˶¯µÄʱ¼ä¼õÈ¥ÈôÒÔÔ­À´ËÙ¶ÈÐÐÊ»Õâ¶ÎλÒÆËùÐèµÄʱ¼ä£®