ÌâÄ¿ÄÚÈÝ
ÈçͼÁ½¸öÍêÈ«ÏàͬµÄÖÊÁ¿ÎªmµÄľ°åA¡¢BÖÃÓÚˮƽµØÃæÉÏ£¬ËüÃǵļä¾às="2.88" m.ÖÊÁ¿Îª2m¡¢´óС¿ÉºöÂÔµÄÎï¿éCÖÃÓÚA°åµÄ×ó¶Ë£¬CÓëAÖ®¼äµÄ¶¯Ä¦²ÁÒòÊýΪ¦Ì1=0.22£¬A¡¢BÓëˮƽµØÃæÖ®¼äµÄ¶¯Ä¦²ÁÒòÊýΪ¦Ì2=0.10£¬×î´ó¾²Ä¦²ÁÁ¦¿ÉÈÏΪµÈÓÚ»¬¶¯Ä¦²ÁÁ¦.¿ªÊ¼Ê±£¬Èý¸öÎïÌå´¦ÓÚ¾²Ö¹×´Ì¬.ÏÖ¸øCÊ©¼ÓÒ»¸öˮƽÏòÓÒ¡¢´óСΪ
mgµÄºãÁ¦F£¬¼Ù¶¨Ä¾°åA¡¢BÅöײʱ¼ä¼«¶ÌÇÒÅöײºóð¤Á¬ÔÚÒ»Æð.ҪʹC×îÖÕ²»ÍÑÀëľ°å£¬Ã¿¿éľ°åµÄ³¤¶ÈÖÁÉÙΪ¶àÉÙ£¿![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241139380621559.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113938015221.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241139380621559.jpg)
0.3 m
ÉèA¡¢CÖ®¼äµÄ»¬¶¯Ä¦²ÁÁ¦´óСΪf1£¬AÓëˮƽÃæÖ®¼äµÄ»¬¶¯Ä¦²ÁÁ¦´óСΪf2
ÒòΪ¦Ì1=0.22£¬¦Ì2=0.10
ËùÒÔF=
mg£¼f1=¦Ì12mgÇÒF=
mg£¾f2=¦Ì2(2m+m)g
ËùÒÔÒ»¿ªÊ¼AºÍC±£³ÖÏà¶Ô¾²Ö¹£¬ÔÚFµÄ×÷ÓÃÏÂÏòÓÒ¼ÓËÙ¶ÈÔ˶¯£¬ÓÐ
£¨F-f2£©s=
¡¤(2m+m)v12
A¡¢BÁ½Ä¾°åÅöײ˲¼ä£¬ÄÚÁ¦Ô¶´óÓÚÍâÁ¦£¬Óɶ¯Á¿Êغ㶨ÂɵÃ
mv1=(m+m)v2
Åöײºóµ½Èý¸öÎïÌå´ïµ½¹²Í¬ËٶȵÄÏ໥×÷Óùý³ÌÖУ¬Éèľ°åÏòÇ°Òƶ¯µÄλÒÆΪs1.
Ñ¡Èý¸öÎïÌå¹¹³ÉµÄÕûÌåΪÑо¿¶ÔÏó£¬ÍâÁ¦Ö®ºÍΪÁ㣬Ôò
2mv1+(m+m)v2=(2m+m+m)v3
ÉèA¡¢BϵͳÓëˮƽµØÃæÖ®¼äµÄ»¬¶¯Ä¦²ÁÁ¦´óСΪf3£¬¶ÔA¡¢Bϵͳ£¬Óɶ¯Äܶ¨Àí
f1s1-f3s1=
¡¤2mv32-
¡¤2mv22
f3=¦Ì2(2m+m+m)g
¶ÔCÓɶ¯Äܶ¨Àí
F¡¤(2l+s1)-f1¡¤(2l+s1)=
¡Á2mv32-
¡Á2mv12
ÓÉÒÔÉϸ÷ʽ£¬ÔÙ´úÈëÊý¾Ý¿ÉµÃl="0.3" m
ÒòΪ¦Ì1=0.22£¬¦Ì2=0.10
ËùÒÔF=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113938015221.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113938015221.gif)
ËùÒÔÒ»¿ªÊ¼AºÍC±£³ÖÏà¶Ô¾²Ö¹£¬ÔÚFµÄ×÷ÓÃÏÂÏòÓÒ¼ÓËÙ¶ÈÔ˶¯£¬ÓÐ
£¨F-f2£©s=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113938140225.gif)
A¡¢BÁ½Ä¾°åÅöײ˲¼ä£¬ÄÚÁ¦Ô¶´óÓÚÍâÁ¦£¬Óɶ¯Á¿Êغ㶨ÂɵÃ
mv1=(m+m)v2
Åöײºóµ½Èý¸öÎïÌå´ïµ½¹²Í¬ËٶȵÄÏ໥×÷Óùý³ÌÖУ¬Éèľ°åÏòÇ°Òƶ¯µÄλÒÆΪs1.
Ñ¡Èý¸öÎïÌå¹¹³ÉµÄÕûÌåΪÑо¿¶ÔÏó£¬ÍâÁ¦Ö®ºÍΪÁ㣬Ôò
2mv1+(m+m)v2=(2m+m+m)v3
ÉèA¡¢BϵͳÓëˮƽµØÃæÖ®¼äµÄ»¬¶¯Ä¦²ÁÁ¦´óСΪf3£¬¶ÔA¡¢Bϵͳ£¬Óɶ¯Äܶ¨Àí
f1s1-f3s1=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113938140225.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113938140225.gif)
f3=¦Ì2(2m+m+m)g
¶ÔCÓɶ¯Äܶ¨Àí
F¡¤(2l+s1)-f1¡¤(2l+s1)=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113938140225.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824113938140225.gif)
ÓÉÒÔÉϸ÷ʽ£¬ÔÙ´úÈëÊý¾Ý¿ÉµÃl="0.3" m
![](http://thumb2018.1010pic.com/images/loading.gif)
Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿