ÌâÄ¿ÄÚÈÝ
9£®ÈçͼËùʾ£¬¾¢¶ÈϵÊýk=1000N/mµÄÇáÖʵ¯»ÉÒ»¶Ë¹Ì¶¨ÔÚǽÉÏ£¬ÁíÒ»¶ËÓëÇã½ÇΪ¦È=37¡ãµÄбÃæÌåС³µMÁ¬½Ó£¬Ð¡³µÖÃÓڹ⻬ˮƽÃæÉÏ£®ÔÚС³µÉϵþ·ÅÒ»¸öСÎï¿ém£¬ÒÑ֪С³µÖÊÁ¿M=3kg£¬Îï¿éÖÊÁ¿m=1kg£¬µ±Ð¡³µÎ»ÓÚOµãʱ£¬Õû¸öϵͳ´¦ÓÚƽºâ״̬£®ÏÖ½«Ð¡³µ´ÓOµã»ºÂýµØÀµ¹Bµã£¬OBµÄ³¤¶ÈL=5cm£»½«Ð¡³µÎÞ³õËÙÊÍ·Å£¬Ð¡³µÔÚˮƽÃæÉϵÄB¡¢C¼äÀ´»ØÍù¸´Ô˶¯£¬B¡¢C¹ØÓÚOµã¶Ô³Æ£¬Îï¿éºÍС³µÖ®¼äʼÖÕÏà¶Ô¾²Ö¹£®Ç󣺣¨È¡g=10m/s2£¬sin37¡ã=0.6£¬cos37¡ã=0.8£©£¨1£©Ð¡³µÎ»ÓÚOµãʱ£¬Îï¿éÊܵ½Ä¦²ÁÁ¦µÄ´óСf1£»
£¨2£©Ð¡³µÔÚBµãʱµÄ¼ÓËٶȴóСaºÍÎï¿éËùÊܵ½Ä¦²ÁÁ¦µÄ´óСf2£»
£¨3£©Ð¡³µÔ˶¯µ½CµãʱС³µ¶ÔÎï¿éÖ§³ÖÁ¦µÄ´óСFC£®
·ÖÎö £¨1£©Ð¡³µÎ»ÓÚOµãʱ£¬¶ÔMºÍmÕûÌåÊÜÁ¦·ÖÎöºó¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉÇó½â³ö¼ÓËٶȣ¬ÔÙ¶Ôm£¬¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉÁÐʽÇó½âĦ²ÁÁ¦f1£®
£¨2£©Ð¡³µÔ˶¯µ½Bµãʱ£¬ÏȶÔMºÍmÕûÌåÊÜÁ¦·ÖÎöºó¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉÇó½â³ö¼ÓËÙ¶Èa£¬È»ºó¶Ôm£¬ÊÜÁ¦·ÖÎöºó¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉÁÐʽÇó½âĦ²ÁÁ¦f2£»
£¨3£©¸ù¾Ý¼òгÔ˶¯µÄ¶Ô³ÆÐԵõ½Ð¡³µÔ˶¯µ½CµãʱµÄ¼ÓËٶȣ¬ÔÙÓÉÅ£¶ÙµÚ¶þ¶¨ÂÉÁÐʽÇó½âС³µ¶ÔÎï¿éÖ§³ÖÁ¦FC£®
½â´ð ½â£º£¨1£©Ð¡³µÎ»ÓÚOµãʱ£¬È¡M¡¢mºÍµ¯»É×é³ÉµÄϵͳΪÑо¿¶ÔÏó£¬ÓÉÅ£¶ÙµÚ¶þ¶¨ÂɵÃ
£¨M+m£©a=0
µÃ a=0
ÔÙ¶Ôm£¬´Ë˲¼ämµÄºÏÁ¦Îª0£¬ÔòÎï¿éÊܵ½Ä¦²ÁÁ¦µÄ´óС f1=mgsin¦È=1¡Á10¡Ásin37¡ã N=6N
£¨2£©Ð¡³µÔÚBµãʱ£¬È¡M¡¢mºÍµ¯»É×é³ÉµÄϵͳΪÑо¿¶ÔÏó£¬ÓÉÅ£¶ÙµÚ¶þ¶¨ÂɵÃ
£¨M+m£©a=kL
ËùÒÔ a=$\frac{kL}{M+m}$=$\frac{1000¡Á0.05}{3+1}$=12.5m/s2£»
È¡mΪÑо¿¶ÔÏó£¬ÊÜÖØÁ¦¡¢Ö§³ÖÁ¦ºÍĦ²ÁÁ¦£¨ÑØбÃæÏòÉÏ £©£¬ÔÚÑØбÃæ·½ÏòÓУº
f2-mgsin¦È=macos¦È£»
½âµÃ f2=m£¨gsin¦È+acos¦È£©=1¡Á£¨10¡Á0.6+12.5¡Á0.8£©N=16N£»
£¨2£©Ð¡³µÔ˶¯µ½Cµãʱ£¬ÓÉÓÚB¡¢C¹ØÓÚOµã¶Ô³Æ£¬¸ù¾Ý¼òгÔ˶¯µÄ¶Ô³ÆÐÔ£¬¹Ê֪С³µÔÚCµãʱµÄ¼ÓËٶȴóСΪa£¬·½ÏòˮƽÏòÓÒ£®
¶Ôm£¬ÔÚ´¹Ö±ÓÚбÃæ·½ÏòÓÐ FC-mgcos¦È=masin¦È
ËùÒÔ FC=m£¨gcos¦È+asin¦È£©=1¡Á£¨10¡Á0.8+12.5¡Á0.6£©N=15.5N
´ð£º
£¨1£©Ð¡³µÎ»ÓÚOµãʱ£¬Îï¿éÊܵ½Ä¦²ÁÁ¦µÄ´óСf1ÊÇ6N£®
£¨2£©Ð¡³µÔÚBµãʱµÄ¼ÓËٶȴóСaºÍÎï¿éËùÊܵ½Ä¦²ÁÁ¦µÄ´óСf2ÊÇ16N£®
£¨3£©Ð¡³µÔ˶¯µ½CµãʱС³µ¶ÔÎï¿éÖ§³ÖÁ¦µÄ´óСFCÊÇ15.5N£®
µãÆÀ ±¾ÌâµÄ¹Ø¼üÏȸù¾ÝÕûÌå·¨Çó½â¼ÓËٶȣ¬È»ºóÔÙ¸ôÀëmÊÜÁ¦·ÖÎö²¢¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉÁÐʽÇó½â£®·ÖÎöʱ£¬»¹Òª³ä·ÖÀûÓüòгÔ˶¯µÄ¶Ô³ÆÐÔ£®
A£® | µçÈÝÆ÷µÄµçÈݼõС | B£® | µçÈÝÆ÷µÄµçÈÝÔö´ó | ||
C£® | Éϼ«°å´øµçºÉÁ¿½«Ôö´ó | D£® | ϼ«°å´øµçºÉÁ¿±£³Ö²»±ä |
A£® | 5T | B£® | 10T | C£® | 15T | D£® | 20T |
A£® | СÇòÊÇ´Ó5m¸ß´¦×ÔÓÉÏÂÂäµÄ | |
B£® | СÇò·´µ¯ÆðµÄ×î´ó¸ß¶ÈΪ0.45m | |
C£® | СÇòµÚÒ»´Î·´µ¯³õËٶȵĴóСΪ3m/s | |
D£® | СÇòÓëµØÃæÅöײµÄËٶȸıäÁ¿Îª2m/s |
A£® | ÐèÒª²âÁ¿Ö§¼ÜÖÊÁ¿ | B£® | ÐèÒªÖªµÀgµÄ´óС | ||
C£® | Æä²âÁ¿ÔÀí¸ù¾Ý¹ßÐÔ¶¨ÂÉ | D£® | Æä²âÁ¿ÔÀí¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉ |
A£® | 0£¼¦Ì£¼0.25 | B£® | 0.25£¼¦Ì£¼0.5 | C£® | 0.5£¼¦Ì£¼0.75 | D£® | 0.75£¼¦Ì£¼1 |
A£® | ½ðÊôÏß¿òµÄתËÙΪ50r/s | |
B£® | t=0.01sʱ£¬´©¹ýÏß¿ò»Ø·µÄ´ÅͨÁ¿ÎªÁã | |
C£® | µçѹ±íµÄʾÊýΪ220V | |
D£® | µÆÅÝÿÃëʵ¼ÊÏûºÄµÄµçÄÜΪ459.8J |
A£® | Óò»¿É¼û¹âÕÕÉä½ðÊôÒ»¶¨±ÈÓÿɼû¹âÕÕÉäͬÖÖ½ðÊô²úÉúµÄ¹âµç×ӵijõ¶¯ÄÜ´ó | |
B£® | °´ÕÕ²£¶ûÀíÂÛ£¬ÇâÔ×ÓºËÍâµç×ӴӰ뾶½ÏСµÄ¹ìµÀԾǨµ½°ë¾¶½Ï´óµÄ¹ìµÀʱ£¬µç×ӵĶ¯ÄܼõС£¬µ«Ô×ÓµÄÄÜÁ¿Ôö´ó | |
C£® | ¹âµç×ÓµÄ×î´ó³õ¶¯ÄÜËæÈëÉä¹âƵÂÊÔö´ó¶øÔö´ó | |
D£® | ÔÚ¹âÕÕÌõ¼þ²»±äµÄÇé¿öÏ£¬¶Ô·¢Éä³öÀ´µÄ¹âµç×Ó¼ÓÉÏÕýÏòµçѹ¶Ô¹âµç×Ó¼ÓËÙ£¬Ëù¼Óµçѹ²»¶ÏÔö´ó£¬¹âµçÁ÷Ò²²»¶ÏÔö´ó |