Question

ÔÚÒ»´ÎÔ¶×ã»î¶¯ÖУ¬Ä³°àѧÉú·Ö³ÉÁ½×飬µÚÒ»×éÓɼ׵ØÔÈËÙ²½Ðе½Òҵغóԭ··µ»Ø£¬µÚ¶þ×éÓɼ׵ØÔÈËÙ²½Ðо­ÒҵؼÌÐøÇ°Ðе½±ûµØºóԭ··µ»Ø£¬Á½×éͬʱ³ö·¢£¬Éè²½ÐеÄʱ¼äΪt£¨h£©£¬Á½×éÀëÒҵصľàÀë·Ö±ðΪS₁£¨km£©ºÍS₂£¨km£©£¬Í¼ÖеÄÕÛÏß·Ö±ð±íʾS₁¡¢S₂ÓëtÖ®¼äµÄº¯Êý¹Øϵ£®
£¨1£©¼×¡¢ÒÒÁ½µØÖ®¼äµÄ¾àÀëΪ

 

km£¬ÒÒ¡¢±ûÁ½µØÖ®¼äµÄ¾àÀëΪ

 

km£»
£¨2£©ÇóµÚ¶þ×éÓɼ׵سö·¢Ê״ε½´ïÒҵؼ°ÓÉÒҵص½´ï±ûµØËùÓõÄʱ¼ä·Ö±ðÊǶàÉÙ£¿
£¨3£©ÇóͼÖÐÏ߶ÎABËù±íʾµÄS₂Óët¼äµÄº¯Êý¹Øϵʽ£¬²¢Ð´³ö×Ô±äÁ¿tµÄÈ¡Öµ·¶Î§£®

Answer 1

·ÖÎö£º£¨1£©¸ù¾Ýº¯ÊýͼÏóÖªµÀµ±S=0ʱ±íʾ´Ó¼×µØµ½ÁËÒҵأ¬ÓÉ´Ë¿ÉÒԵõ½¼×¡¢ÒÒÁ½µØÖ®¼äµÄ¾àÀ룬ͬÑùµÄ·½·¨µÃµ½ÒÒ¡¢±ûÁ½µØÖ®¼äµÄ¾àÀ룻
£¨2£©ÓÉͼÏó¿ÉÖª£¬µÚ¶þ×éÒ»¹²×ßÁË2Сʱ£¬×Ü·³ÌΪ8+2+2+8=20ǧÃ×£¬¼´ÆäËÙ¶ÈΪ10ǧÃ×/ʱ£¬¶øÆäÓɼ׵سö·¢Ê״ε½ÒÒµØËù×ߵķ³ÌΪ8ǧÃ×£¬ÓÉÒҵص½±ûµØµÄ·³ÌΪ2ǧÃ×£¬ÀûÓÃʱ¼ä=·³Ì¡ÂËٶȼ´¿ÉÇó³öÁ½¸öʱ¼ä£»
£¨3£©ÓÉ£¨2£©¿ÉÖª£¬A£¨0.8£¬0£©£¬B£¨0.2+0.8£¬2£©£¬Éès₂=kt+b£¬½«A¡¢BÁ½µãµÄ×ø±ê´úÈ룬½¨Á¢·½³Ì×飬¼´¿ÉÇó½â£®

½â´ð£º½â£º£¨1£©¸ù¾ÝͼÏóÖªµÀ£º¼×¡¢ÒÒÁ½µØÖ®¼äµÄ¾àÀëΪ8km£¬ÒÒ¡¢±ûÁ½µØÖ®¼äµÄ¾àÀëΪ2km£»

£¨2£©µÚ¶þ×éÓɼ׵سö·¢Ê״ε½´ïÒÒµØËùÓõÄʱ¼äΪ
8¡Â[2¡Á£¨8+2£©¡Â2]=8¡Â10=0.8£¨Ð¡Ê±£©
µÚ¶þ×éÓÉÒҵص½´ï±ûµØËùÓõÄʱ¼äΪ
2¡Â[2¡Á£¨8+2£©¡Â2]=2¡Â10=0.2£¨Ð¡Ê±£©£»

£¨3£©¸ù¾ÝÌâÒâµÃA¡¢BµÄ×ø±ê·Ö±ðΪ£¨0.8£¬0£©ºÍ£¨1£¬2£©
ÉèÏ߶ÎABµÄº¯Êý¹ØϵʽΪ£ºS₂=kt+b
¸ù¾ÝÌâÒ⣬µÃ
¡à

0=0.8k+b 2=k+b

½âµÃ

k=10 b=-8

¡àͼÖÐÏ߶ÎABËù±íʾµÄS₂Óët¼äµÄº¯Êý¹ØϵʽΪS₂=10t-8£¬×Ô±äÁ¿tµÄÈ¡Öµ·¶Î§ÊÇ0.8¡Üt¡Ü1£®

µãÆÀ£º±¾ÌâÐè×Ðϸ·ÖÎöÌâÒ⣬½áºÏͼÏó£¬ÀûÓôý¶¨ÏµÊý·¨²Å¿É½â¾öÎÊÌ⣮½â´ðÒ»´Îº¯ÊýµÄÓ¦ÓÃÎÊÌâÖУ¬Òª×¢Òâ×Ô±äÁ¿µÄÈ¡Öµ·¶Î§»¹±ØÐëʹʵ¼ÊÎÊÌâÓÐÒâÒ壮