ÌâÄ¿ÄÚÈÝ
(1)µØÕð²¨ÖмÈÓкᲨÓÖÓÐ×ݲ¨£®ÈçͼËùʾ£¬¼×ÊÇÈÕ±¾µØÕðÖеÄÒ»ÁкᲨÔÚt£½0ʱ¿ÌµÄ²¨ÐÎͼ£¬ÒÒΪÓÉÕâÁкᲨÒýÆðµÄx£½2 km´¦ÖʵãµÄÕñ¶¯Í¼Ïó£®
¡¡![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250036092283023.jpg)
¢ÙÏÖ²âµÃ¸Ãºá²¨´ÓÕðÖд«µ½ÏĘ́µÄʱ¼äÊÇ45 s£¬ÕðÖоàÀëÏĘ́ÓжàÔ¶£¿
¢ÚÅжϲ¨µÄ´«²¥·½Ïò£¬²¢È·¶¨t£½1.75 sʱ£¬x£½4 km´¦µÄÖʵãµÄλÒÆ£®
(2)Èçͼ£¬Ò»¸öÈýÀâ¾µµÄ½ØÃæΪµÈÑüÖ±½ÇÈý½ÇÐÎABC.Ò»Êø¹âÏßÑØƽÐÐÓÚBC±ßµÄ·½ÏòÉäµ½AB±ß£¬½øÈëÀâ¾µºóÖ±½ÓÉäµ½AC±ßÉÏ£¬ÒªÇó¹âÏß²»ÄÜÖ±½Ó´ÓAC½çÃæÉä³ö£¬ÄÇôÈýÀâ¾µµÄÕÛÉäÂÊÐèÒªÂú×ãʲôÌõ¼þ£¿
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250036092442634.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250036091973284.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250036092283023.jpg)
¢ÙÏÖ²âµÃ¸Ãºá²¨´ÓÕðÖд«µ½ÏĘ́µÄʱ¼äÊÇ45 s£¬ÕðÖоàÀëÏĘ́ÓжàÔ¶£¿
¢ÚÅжϲ¨µÄ´«²¥·½Ïò£¬²¢È·¶¨t£½1.75 sʱ£¬x£½4 km´¦µÄÖʵãµÄλÒÆ£®
(2)Èçͼ£¬Ò»¸öÈýÀâ¾µµÄ½ØÃæΪµÈÑüÖ±½ÇÈý½ÇÐÎABC.Ò»Êø¹âÏßÑØƽÐÐÓÚBC±ßµÄ·½ÏòÉäµ½AB±ß£¬½øÈëÀâ¾µºóÖ±½ÓÉäµ½AC±ßÉÏ£¬ÒªÇó¹âÏß²»ÄÜÖ±½Ó´ÓAC½çÃæÉä³ö£¬ÄÇôÈýÀâ¾µµÄÕÛÉäÂÊÐèÒªÂú×ãʲôÌõ¼þ£¿
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250036092442634.jpg)
(1)¢Ù180 km¡¡¢Ú£10 m¡¡(2)n¡Ý![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003609259471.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003609259471.png)
(1)¢ÙÓɼ×ͼ֪£º¦Ë£½4 km£¬Óɲ¨ËÙ¹«Ê½µÃ£ºv£½
¢Ù
ÏĘ́ÓëÕðÖеľàÀëΪx£½vt ¢Ú
T£½1 s£¬t£½45 s
ÁªÁ¢¢Ù¢Úʽ£¬´úÈëÊý¾ÝµÃ£ºx£½180 km.
¢ÚÓÉͼÒÒÖª£¬t£½0ʱ¿ÌÖʵãÑØyÖḺÏòÔ˶¯£¬¹Ê²¨ÑØxÖḺÏò´«²¥£®
ÓÉÌâÒâÖª£ºT£½1 s£¬t£½1
T£¬
t£½1.75 sʱ£¬x£½4 kmÖʵãµÄλÒÆΪ£10 m.
(2)ÓɹâµÄÕÛÉ䶨ÂÉÖª£º
£½n ¢Ù
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250036093372840.jpg)
ÒªÏë¹âÏß²»´ÓAC½çÃæÉä³ö£¬±ØÐëÓÐ
sin ¦È3¡Ý
¢Ú
¸ù¾Ý¼¸ºÎ¹Øϵ£º¦È1£½45¡ã£¬¦È2£«¦È3£½90¡ã ¢Û
ÁªÁ¢¢Ù¢Ú¢Û¢ÜµÃ£ºn¡Ý
. ¢Ü
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003609291427.png)
ÏĘ́ÓëÕðÖеľàÀëΪx£½vt ¢Ú
T£½1 s£¬t£½45 s
ÁªÁ¢¢Ù¢Úʽ£¬´úÈëÊý¾ÝµÃ£ºx£½180 km.
¢ÚÓÉͼÒÒÖª£¬t£½0ʱ¿ÌÖʵãÑØyÖḺÏòÔ˶¯£¬¹Ê²¨ÑØxÖḺÏò´«²¥£®
ÓÉÌâÒâÖª£ºT£½1 s£¬t£½1
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003609306385.png)
t£½1.75 sʱ£¬x£½4 kmÖʵãµÄλÒÆΪ£10 m.
(2)ÓɹâµÄÕÛÉ䶨ÂÉÖª£º
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003609322630.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250036093372840.jpg)
ÒªÏë¹âÏß²»´ÓAC½çÃæÉä³ö£¬±ØÐëÓÐ
sin ¦È3¡Ý
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003609369348.png)
¸ù¾Ý¼¸ºÎ¹Øϵ£º¦È1£½45¡ã£¬¦È2£«¦È3£½90¡ã ¢Û
ÁªÁ¢¢Ù¢Ú¢Û¢ÜµÃ£ºn¡Ý
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003609259471.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿