ÌâÄ¿ÄÚÈÝ
Èçͼ£¬QΪһ¸öÔÀ´¾²Ö¹Ôڹ⻬ˮƽÃæÉϵÄÎïÌ壬ÆäDB¶ÎΪһ°ë¾¶ÎªRµÄ¹â»¬Ô²»¡¹ìµÀ£¬AD¶ÎΪһ³¤¶ÈΪL=RµÄ´Ö²Úˮƽ¹ìµÀ£¬¶þÕßÏàÇÐÓÚDµã£¬DÔÚÔ²ÐÄOµÄÕýÏ·½£¬Õû¸ö¹ìµÀλÓÚͬһÊúֱƽÃæÄÚ£®Îï¿éPµÄÖÊÁ¿Îªm£¨¿ÉÊÓΪÖʵ㣩£¬PÓëAD¼äµÄ¶¯Ä¦²ÁÒòÊý¦Ì=0.1£¬ÎïÌåQµÄÖÊÁ¿ÎªM=2m£¬ÖØÁ¦¼ÓËÙ¶ÈΪg£®£¨1£©ÈôQ¹Ì¶¨£¬PÒÔËÙ¶Èv´ÓAµã»¬ÉÏˮƽ¹ìµÀ£¬³åÖÁCµãºó·µ»ØAµãʱǡºÃ¾²Ö¹£¬ÇóvµÄ´óСºÍP¸ÕÔ½¹ýDµãʱ¶ÔQµÄѹÁ¦´óС£®
£¨2£©ÈôQ²»¹Ì¶¨£¬PÈÔÒÔËÙ¶Èv´ÓAµã»¬ÉÏˮƽ¹ìµÀ£¬ÇóPÔڹ⻬Բ»¡¹ìµÀÉÏËùÄÜ´ïµ½µÄ×î´ó¸ß¶Èh£®
¡¾´ð°¸¡¿·ÖÎö£º£¨1£©P´ÓAµ½CÓÖ·µ»ØAµÄ¹ý³ÌÖУ¬Óɶ¯Äܶ¨ÀíÇóµÃvµÄ´óС£¬Óɶ¯Äܶ¨ÀíºÍÅ£¶Ù¶¨ÂÉÇó½â¶ÔQµÄѹÁ¦´óС£®
£¨2£©µ±PQ¾ßÓй²Í¬ËÙ¶Èvʱ£¬P´ïµ½µÄ×î´ó¸ß¶Èh£¬Óɶ¯Á¿Êغ㶨Âɺ͹¦ÄܹØϵÇó½â£®
½â´ð£º½â£º£¨1£©P´ÓAµ½CÓÖ·µ»ØAµÄ¹ý³ÌÖУ¬Óɶ¯Äܶ¨ÀíÓÐ
-¦Ìmg?2L=0-m ¢Ù
½«L=R´úÈë¢Ù½âµÃ
v= ¢Ú
ÈôPÔÚDµãµÄËÙ¶ÈΪvD£¬Q¶ÔPµÄÖ§³ÖÁ¦ÎªFD£¬Óɶ¯Äܶ¨ÀíºÍÅ£¶Ù¶¨ÂÉÓÐ
-¦ÌmgL=m-m ¢Û
¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂɵÃ
FD-mg=m ¢Ü
ÁªÁ¢½âµÃ
FD=1.2mg ¢Ý
ÓÉÅ£¶ÙµÚÈý¶¨ÂÉ¿ÉÖª£¬P¶ÔQµÄѹÁ¦´óСҲΪ1.2mg£®
£¨2£©µ±PQ¾ßÓй²Í¬ËÙ¶Èvʱ£¬P´ïµ½µÄ×î´ó¸ß¶Èh£¬Óɶ¯Á¿Êغ㶨ÂÉÓÐ
mv=£¨m+M£©v ¢Þ
Óɹ¦ÄܹØϵÓÐ
m=¦ÌmgL+£¨m+M£©v2+mgh ¢ß
ÁªÁ¢½âµÃ
h=R
´ð£º£¨1£©ÈôQ¹Ì¶¨£¬PÒÔËÙ¶Èv´ÓAµã»¬ÉÏˮƽ¹ìµÀ£¬³åÖÁCµãºó·µ»ØAµãʱǡºÃ¾²Ö¹£¬vµÄ´óСÊÇ£¬P¸ÕÔ½¹ýDµãʱ¶ÔQµÄѹÁ¦´óСÊÇ1.2mg£®
£¨2£©ÈôQ²»¹Ì¶¨£¬PÈÔÒÔËÙ¶Èv´ÓAµã»¬ÉÏˮƽ¹ìµÀ£¬PÔڹ⻬Բ»¡¹ìµÀÉÏËùÄÜ´ïµ½µÄ×î´ó¸ß¶ÈhÊÇR£®
µãÆÀ£º±¾ÌâÖ÷Òª¿¼²éÁËÅ£¶ÙµÚ¶þ¶¨ÂÉ¡¢¶¯Á¿Êغ㶨Âɼ°¶¯Äܶ¨ÀíµÄÖ±½ÓÓ¦Óã¬ÄѶÈÊÊÖУ®
£¨2£©µ±PQ¾ßÓй²Í¬ËÙ¶Èvʱ£¬P´ïµ½µÄ×î´ó¸ß¶Èh£¬Óɶ¯Á¿Êغ㶨Âɺ͹¦ÄܹØϵÇó½â£®
½â´ð£º½â£º£¨1£©P´ÓAµ½CÓÖ·µ»ØAµÄ¹ý³ÌÖУ¬Óɶ¯Äܶ¨ÀíÓÐ
-¦Ìmg?2L=0-m ¢Ù
½«L=R´úÈë¢Ù½âµÃ
v= ¢Ú
ÈôPÔÚDµãµÄËÙ¶ÈΪvD£¬Q¶ÔPµÄÖ§³ÖÁ¦ÎªFD£¬Óɶ¯Äܶ¨ÀíºÍÅ£¶Ù¶¨ÂÉÓÐ
-¦ÌmgL=m-m ¢Û
¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂɵÃ
FD-mg=m ¢Ü
ÁªÁ¢½âµÃ
FD=1.2mg ¢Ý
ÓÉÅ£¶ÙµÚÈý¶¨ÂÉ¿ÉÖª£¬P¶ÔQµÄѹÁ¦´óСҲΪ1.2mg£®
£¨2£©µ±PQ¾ßÓй²Í¬ËÙ¶Èvʱ£¬P´ïµ½µÄ×î´ó¸ß¶Èh£¬Óɶ¯Á¿Êغ㶨ÂÉÓÐ
mv=£¨m+M£©v ¢Þ
Óɹ¦ÄܹØϵÓÐ
m=¦ÌmgL+£¨m+M£©v2+mgh ¢ß
ÁªÁ¢½âµÃ
h=R
´ð£º£¨1£©ÈôQ¹Ì¶¨£¬PÒÔËÙ¶Èv´ÓAµã»¬ÉÏˮƽ¹ìµÀ£¬³åÖÁCµãºó·µ»ØAµãʱǡºÃ¾²Ö¹£¬vµÄ´óСÊÇ£¬P¸ÕÔ½¹ýDµãʱ¶ÔQµÄѹÁ¦´óСÊÇ1.2mg£®
£¨2£©ÈôQ²»¹Ì¶¨£¬PÈÔÒÔËÙ¶Èv´ÓAµã»¬ÉÏˮƽ¹ìµÀ£¬PÔڹ⻬Բ»¡¹ìµÀÉÏËùÄÜ´ïµ½µÄ×î´ó¸ß¶ÈhÊÇR£®
µãÆÀ£º±¾ÌâÖ÷Òª¿¼²éÁËÅ£¶ÙµÚ¶þ¶¨ÂÉ¡¢¶¯Á¿Êغ㶨Âɼ°¶¯Äܶ¨ÀíµÄÖ±½ÓÓ¦Óã¬ÄѶÈÊÊÖУ®
Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿