ÌâÄ¿ÄÚÈÝ

9£®ÈçͼËùʾ£¬³¤ÎªL=7.75mµÄˮƽ´«ËÍ´øÒÔËÙ¶Èv1=6m/sÔÈËÙÔ˶¯£¬ÖÊÁ¿¾ùΪmµÄСÎïÌåP¡¢QÓÉͨ¹ý¶¨»¬ÂÖÇÒ²»¿ÉÉ쳤µÄÇáÉþÏàÁ¬£¬Ä³Ê±¿ÌPÔÚ´«ËÍ´ø×ó¶Ë¾ßÓÐÏòÓÒµÄËÙ¶Èv2=9m/s£¬PÓ붨»¬ÂÖ¼äµÄÉþˮƽ£¬PÓë´«ËÍ´ø¼äµÄ¶¯Ä¦²ÁÒòÊýΪ¦Ì=0.2£¬ÖØÁ¦¼ÓËÙ¶Èg=10m/s2£¬²»¼Æ¶¨»¬ÂÖÖÊÁ¿ºÍĦ²Á£¬Éþ×ã¹»³¤£®Çó£º
£¨1£©PÎïÌå¸Õ¿ªÊ¼ÔÚ´«ËÍ´øÉÏÔ˶¯µÄ¼ÓËÙ¶È´óС£»
£¨2£©PÎïÌåËÙ¶ÈÓë´«ËÍ´øËÙ¶ÈÏàµÈʱÆäÏòÓÒÔ˶¯µÄÎ»ÒÆ´óС£»
£¨3£©PÎïÌåÔÚ´«ËÍ´øÉÏÔ˶¯µÄ×Üʱ¼ä£®

·ÖÎö £¨1£©¶ÔP¡¢Q¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉÁз½³ÌÇóPÎïÌå¸Õ¿ªÊ¼ÔÚ´«ËÍ´øÉÏÔ˶¯µÄ¼ÓËÙ¶È´óС
£¨2£©PÏÈÒÔ¼ÓËÙ¶Èa1Ïò×ó×öÔȼõËÙÔ˶¯£¬Ö±µ½ËٶȼõΪ${v}_{1}^{\;}$£¬¸ù¾ÝËÙ¶Èʱ¼ä¹ØÏµÇó³öʱ¼ä${t}_{1}^{\;}$£¬ÔÙÓÉ$x=\frac{{v}_{1}^{\;}+{v}_{2}^{\;}}{2}{t}_{1}^{\;}$ÇóÏòÓÒÔ˶¯µÄÎ»ÒÆ´óС
£¨3£©ËÙ¶ÈÏàµÈÒÔºó½Ó×ÅÒÔ¼ÓËÙ¶Èa2Ïò×ó×öÔȼõËÙÔ˶¯£¬ÓÉÅ£¶ÙµÚ¶þ¶¨ÂÉÇó³ö${a}_{2}^{\;}$£¬ÓÉËÙ¶ÈÎ»ÒÆ¹«Ê½Çó³öÎï¿éµ½´«ËÍ´øÓҶ˵ÄËÙ¶È£¬¸ù¾ÝËÙ¶Èʱ¼ä¹ØÏµÇó³öËÙ¶ÈÏàµÈºóÔ˶¯µÄʱ¼ä${t}_{2}^{\;}$£¬¼´¿ÉÇó³ö×Üʱ¼ä

½â´ð ½â£º£¨1£©ÉèP¿ªÊ¼×ö¼õËÙÔ˶¯µÄ¼ÓËÙ¶ÈΪa1£¬¶ÔPÓР T+¦Ìmg=ma1
¶ÔQÓР mg-T=ma1
½âµÃa1=6m/s2   
£¨2£©¾­Ê±¼ät1Óë´«ËÍ´ø´ïÏàͬËÙ¶È£¬${t}_{1}^{\;}=\frac{{v}_{2}^{\;}-{v}_{1}^{\;}}{{a}_{1}^{\;}}=\frac{9-6}{6}s=0.5s$
ÔÚʱ¼ät1ÄÚPµÄÎ»ÒÆ${x}_{1}^{\;}=\frac{{v}_{1}^{\;}+{v}_{2}^{\;}}{2}{t}_{1}^{\;}=\frac{6+9}{2}¡Á0.5=3.75m$
£¨3£©´ï¹²Í¬ËٶȺóÏòÓÒ¼õËÙÔ˶¯£¬¼ÓËÙ¶È´óСΪa2£¬¶ÔPÓР T¡ä-¦Ìmg=ma2
¶ÔQÓР mg-T¡ä=ma2
½âµÃa2=4m/s2
Pµ½´ï´«ËÍ´øµÄÓÒ¶ËËÙ¶ÈΪ$v=\sqrt{{v}_{1}^{2}-2{a}_{2}^{\;}£¨L-{x}_{1}^{\;}£©}$=$\sqrt{{6}_{\;}^{2}-2¡Á4¡Á£¨7.75-3.75£©}$=2m/s
PÔËËÍʱ¼äΪ${t}_{2}^{\;}=\frac{{v}_{1}^{\;}-v}{{a}_{2}^{\;}}=\frac{6-2}{4}=1s$
×Üʱ¼äΪt=t1+t2=1.5s
´ð£º£¨1£©PÎïÌå¸Õ¿ªÊ¼ÔÚ´«ËÍ´øÉÏÔ˶¯µÄ¼ÓËÙ¶È´óС6m/s2£»
£¨2£©PÎïÌåËÙ¶ÈÓë´«ËÍ´øËÙ¶ÈÏàµÈʱÆäÏòÓÒÔ˶¯µÄÎ»ÒÆ´óСΪ3.75m
£¨3£©PÎïÌåÔÚ´«ËÍ´øÉÏÔ˶¯µÄʱ¼äΪ1.5s£®

µãÆÀ ±¾ÌâÖ÷Òª¿¼²éÁËÎïÌåÔÚ´«ËÍ´øÉϵÄÔ˶¯¹ý³Ì£¬·ÖÇå¹ý³ÌÊǹؼü£¬Ìرð×¢ÒâĦ²ÁÁ¦·½ÏòµÄ¸Ä±ä

Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿

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

¾«Ó¢¼Ò½ÌÍø