ÌâÄ¿ÄÚÈÝ
ͼʾΪÐÞ½¨¸ß²ã½¨Öþ³£ÓõÄËþʽÆðÖØ»ú¡£ÔÚÆðÖØ»ú½«ÖÊÁ¿m=5¡Á103 kgµÄÖØÎïÊúÖ±µõÆðµÄ¹ý³ÌÖУ¬ÖØÎïÓɾ²Ö¹¿ªÊ¼ÏòÉÏ×÷ÔȼÓËÙÖ±ÏßÔ˶¯£¬¼ÓËÙ¶Èa="0.2" m/s2£¬µ±ÆðÖØ»úÊä³ö¹¦ÂÊ´ïµ½ÆäÔÊÐíµÄ×î´óֵʱ£¬±£³Ö¸Ã¹¦ÂÊÖ±µ½ÖØÎï×övm="1.02" m/sµÄÔÈËÙÔ˶¯¡£È¡g="10" m/s2,²»¼Æ¶îÍ⹦¡£Çó£º
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241638098734255.jpg)
£¨1£©ÆðÖØ»úÔÊÐíÊä³öµÄ×î´ó¹¦ÂÊ¡£
£¨2£©ÖØÎï×öÔȼÓËÙÔ˶¯Ëù¾ÀúµÄʱ¼äºÍÆðÖØ»úÔÚµÚ2ÃëÄ©µÄÊä³ö¹¦ÂÊ¡£
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241638098734255.jpg)
£¨1£©ÆðÖØ»úÔÊÐíÊä³öµÄ×î´ó¹¦ÂÊ¡£
£¨2£©ÖØÎï×öÔȼÓËÙÔ˶¯Ëù¾ÀúµÄʱ¼äºÍÆðÖØ»úÔÚµÚ2ÃëÄ©µÄÊä³ö¹¦ÂÊ¡£
£¨1£©5.1¡Á104W£¨2£©2.04¡Á104W
ÊÔÌâ·ÖÎö£º(1)ÉèÆðÖØ»úÔÊÐíÊä³öµÄ×î´ó¹¦ÂÊΪP0£¬ÖØÎï´ïµ½×î´óËÙ¶Èʱ£¬ÀÁ¦F0µÈÓÚÖØÁ¦¡£
P0£½F0vm F0£½mg
´úÈëÊý¾Ý£¬ÓУºP0£½5.1¡Á104W £¨4·Ö£©
(2)ÔȼÓËÙÔ˶¯½áÊøʱ£¬ÆðÖØ»ú´ïµ½ÔÊÐíÊä³öµÄ×î´ó¹¦ÂÊ£¬Éè´ËʱÖØÎïÊܵ½µÄÀÁ¦ÎªF£¬ËÙ¶ÈΪv1£¬ÔȼÓËÙÔ˶¯¾Àúʱ¼äΪt1,ÓУº
P0£½Fv1 F£mg£½ma v1£½at1
´úÈëÊý¾Ý£¬µÃ£ºt1£½5 s £¨2·Ö£©
t£½2 sʱ£¬ÖØÎï´¦ÓÚÔȼÓËÙÔ˶¯½×¶Î£¬Éè´ËʱËÙ¶ÈΪv2£¬Êä³ö¹¦ÂÊΪP£¬Ôò
v2£½at P£½Fv2
´úÈëÊý¾Ý£¬µÃ:P£½2.04¡Á104W¡£ £¨2·Ö£©
µãÆÀ£º¸ßÖÐÎïÀíÖУ¬·ÖÎöÊÜÁ¦ºÍÎïÀí¹ý³ÌÊǷdz£ÖØÒªµÄ£®×î´ó¹¦ÂÊÒªÓõÚÈý½×¶ÎÖеÄ
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163809904790.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163810107405.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824163810294987.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿