ÌâÄ¿ÄÚÈÝ

Èçͼ£¨1£©£¬EΪ¾ØÐÎABCD±ßADÉÏÒ»µã£¬µãP´ÓµãBÑØÕÛÏßBE-ED-DCÔ˶¯µ½µãCʱֹͣ£¬µãQ´ÓµãBÑØBCÔ˶¯µ½µãCʱֹͣ£¬ËüÃÇÔ˶¯µÄËٶȶ¼ÊÇ1cm/s£®Èç¹ûµãP¡¢Qͬʱ¿ªÊ¼Ô˶¯£¬ÉèÔ˶¯Ê±¼äΪt£¨s£©£¬¡÷BPQµÄÃæ»ýΪy£¨cm2£©£¬ÒÑÖªyÓëtµÄº¯Êý¹ØÏµµÄͼÏóÈçͼ£¨2£©Ëùʾ£¬ÄÇôÏÂÁнáÂÛÕýÈ·µÄÊÇ£¨¡¡¡¡£©
A¡¢AE=8
B¡¢µ±0¡Üt¡Ü10ʱ£¬y=
2
5
t2
C¡¢sin¡ÏEBD=
4
5
D¡¢µ±t=12sʱ£¬¡÷BPQÊǵÈÑüÈý½ÇÐÎ
¿¼µã£º¶¯µãÎÊÌâµÄº¯ÊýͼÏó
רÌ⣺
·ÖÎö£ºÓÉͼ2¿ÉÖª£¬Ôڵ㣨10£¬40£©ÖÁµã£¨14£¬40£©Çø¼ä£¬¡÷BPQµÄÃæ»ý²»±ä£¬Òò´Ë¿ÉÍÆÂÛBC=BE£¬ÓÉ´Ë·ÖÎö¶¯µãPµÄÔ˶¯¹ý³ÌÈçÏ£º
£¨1£©ÔÚBE¶Î£¬BP=BQ£»³ÖÐøÊ±¼ä10s£¬ÔòBE=BC=10£»yÊÇtµÄ¶þ´Îº¯Êý£»
£¨2£©ÔÚED¶Î£¬y=40ÊǶ¨Öµ£¬³ÖÐøÊ±¼ä4s£¬ÔòED=4£»
£¨3£©ÔÚDC¶Î£¬y³ÖÐø¼õСֱÖÁΪ0£¬yÊÇtµÄÒ»´Îº¯Êý£®
½â´ð£º½â£º£¨1£©½áÂÛA´íÎó£®ÀíÓÉÈçÏ£º
·ÖÎöº¯ÊýͼÏó¿ÉÖª£¬BC=10cm£¬ED=4cm£¬¹ÊAE=AD-ED=BC-ED=10-4=6cm£»

£¨2£©½áÂÛBÕýÈ·£®ÀíÓÉÈçÏ£º
Èç´ðͼ2Ëùʾ£¬¹ýµãP×÷PG¡ÍBQÓÚµãG£¬
¡ßBQ=BP=t£¬
¡ày=S¡÷BPQ=
1
2
BQ•PG=
1
2
BQ•BP•sin¡ÏEBC=
1
2
t•t•
4
5
=
2
5
t2£®

£¨3£©½áÂÛC´íÎó£®ÀíÓÉÈçÏ£º
Èç´ðͼ1Ëùʾ£¬Á¬½ÓEC£¬¹ýµãE×÷EF¡ÍBCÓÚµãF£¬
Óɺ¯ÊýͼÏó¿ÉÖª£¬BC=BE=10cm£¬S¡÷BEC=40=
1
2
BC•EF=
1
2
¡Á10¡ÁEF£¬¡àEF=8£¬
¡àsin¡ÏEBC=
EF
BE
=
8
10
=
4
5
£»

£¨4£©½áÂÛD´íÎó£®ÀíÓÉÈçÏ£º
µ±t=12sʱ£¬µãQÓëµãCÖØºÏ£¬µãPÔ˶¯µ½EDµÄÖе㣬ÉèΪN£¬Èç´ðͼ3Ëùʾ£¬Á¬½ÓNB£¬NC£®
´ËʱAN=8£¬ND=2£¬Óɹ´¹É¶¨ÀíÇóµÃ£ºNB=8
2
£¬NC=
17
£¬
¡ßBC=10£¬
¡à¡÷BCN²»ÊǵÈÑüÈý½ÇÐΣ¬¼´´Ëʱ¡÷PBQ²»ÊǵÈÑüÈý½ÇÐΣ®
¹ÊÑ¡£ºB£®
µãÆÀ£º±¾Ì⿼²é¶¯µãÎÊÌâµÄº¯ÊýͼÏó£¬ÐèÒª½áºÏ¼¸ºÎͼÐÎÓ뺯ÊýͼÏó£¬ÈÏÕæ·ÖÎö¶¯µãµÄÔ˶¯¹ý³Ì£®Í»ÆÆµãÔÚÓÚÕýÈ·ÅжϳöBC=BE=10cm£®
Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿

Î¥·¨ºÍ²»Á¼ÐÅÏ¢¾Ù±¨µç»°£º027-86699610 ¾Ù±¨ÓÊÏ䣺58377363@163.com

¾«Ó¢¼Ò½ÌÍø