ÌâÄ¿ÄÚÈÝ
3£®ÈçͼËùʾ£¬ÖÊÁ¿Îªm1µÄÎïÌå¼×ͨ¹ýÈý¶ÎÇáÉþÐü¹Ò£¬Èý¶ÎÇáÉþµÄ½áµãΪO£¬ÇáÉþOBˮƽÇÒB¶ËÓë·ÅÖÃÔÚˮƽÃæÉϵÄÖÊÁ¿Îªm2µÄÎïÌåÒÒÏàÁ¬£¬ÇáÉþOAÓëÊúÖ±·½ÏòµÄ¼Ð½Ç¦È=37¡ã£¬ÎïÌå¼×¡¢ÒÒ¾ù´¦ÓÚ¾²Ö¹×´Ì¬£®£¨ÒÑÖªsin37¡ã=0.6£¬cos37¡ã=0.8£¬tan37¡ã=0.75£¬gÈ¡10m/s2£®Éè×î´ó¾²Ä¦²ÁÁ¦µÈÓÚ»¬¶¯Ä¦²ÁÁ¦£©Ç󣺣¨1£©ÇáÉþOA¡¢OBÊܵ½µÄÀÁ¦ÊǶà´ó£¿
£¨2£©ÎïÌåÒÒÊܵ½µÄĦ²ÁÁ¦ÊǶà´ó£¿·½ÏòÈçºÎ£¿
£¨3£©ÈôÎïÌåÒÒµÄÖÊÁ¿m2=8kg£¬ÎïÌåÒÒÓëˮƽÃæÖ®¼äµÄ¶¯Ä¦²ÁÒòÊýΪ¦Ì=0.6£¬Èý¶ÎÇáÉþÄܳÐÊܵÄ×î´óÀÁ¦¾ùΪ70N£¬ÔòÓûʹÎïÌåÒÒÔÚˮƽÃæÉϲ»»¬¶¯Í¬Ê±Éþ×Ó²»¶Ï£¬ÎïÌå¼×µÄÖÊÁ¿m1×î´ó²»Äܳ¬¹ý¶àÉÙ£¿
·ÖÎö £¨1£©ÒÔ½áµãOΪÑо¿¶ÔÏ󣬷ÖÎöÊÜÁ¦£¬×÷³öÁ¦Í¼£¬¸ù¾ÝƽºâÌõ¼þÇó³öÇáÉþOA¡¢OBÊܵ½µÄÀÁ¦£®
£¨2£©ÒÒÎïÌåˮƽ·½ÏòÊܵ½OBÉþµÄÀÁ¦ºÍˮƽÃæµÄ¾²Ä¦²ÁÁ¦£¬ÓɶþÁ¦Æ½ºâÇó½âÒÒÊܵ½µÄĦ²ÁÁ¦´óСºÍ·½Ïò£®
£¨3£©µ±ÒÒÎïÌå¸ÕÒª»¬¶¯Ê±£¬Çó³öOAÀÁ¦´óС£¬ÅжÏÉþ×ÓÊÇ·ñÀ¶Ï£¬ÓÉ´ËÔÙ¸ù¾ÝÉþ×ÓÀ¶ÏʱµÄÀÁ¦Çó½â¼×µÄÖÊÁ¿£®
½â´ð ½â£º£¨1£©¶Ô½áµãO£¬×÷³öÁ¦Í¼Èçͼ£¬ÓÉƽºâÌõ¼þÓУº
TA=$\frac{{m}_{1}g}{cos¦È}$=$\frac{5}{4}{m}_{1}g$£»
TB=m1gtan¦È=$\frac{3}{4}{m}_{1}g$£»
£¨2£©¶ÔÓÚÒÒÎïÌ壬¸ù¾Ý¹²µãÁ¦µÄƽºâÌõ¼þ¿É֪Ħ²ÁÁ¦Îª£º
f=TB=$\frac{3}{4}{m}_{1}g$£»
·½ÏòˮƽÏò×ó£»
£¨3£©µ±ÒÒÎïÌå¸ÕÒª»¬¶¯Ê±£¬¾²Ä¦²ÁÁ¦´ïµ½×î´óֵΪ£º
fm=¦Ìm2g=0.6¡Á80N=48N=TB¡ä£¬
´ËʱAÉþµÄÀÁ¦´óСΪ£ºTA¡ä=$\frac{{T}_{B}¡ä}{sin¦È}=\frac{48}{0.6}N=80N$£¾70N£¬ËùÒÔ´ËʱOAÉþ×ÓÒѾÀ¶Ï£»
Òò´ËÓûʹÎïÌåÒÒÔÚˮƽÃæÉϲ»»¬¶¯Í¬Ê±Éþ×Ó²»¶Ï£¬ÔòOA²»¶Ï¼´¿É£¬Óɴ˵õ½ÎïÌå¼×µÄ×î´óÖØÁ¦Îª£º
m1¡äg=TAmcos¦È=70¡Á0.8N=56N£¬
ËùÒÔÎïÌå¼×µÄÖÊÁ¿m1×î´ó²»Äܳ¬¹ý$\frac{56}{10}kg=5.6kg$£®
´ð£º£¨1£©ÇáÉþOAÀÁ¦Îª$\frac{5}{4}{m}_{1}g$¡¢OBÊܵ½µÄÀÁ¦Îª$\frac{3}{4}{m}_{1}g$£»
£¨2£©ÎïÌåÒÒÊܵ½µÄĦ²ÁÁ¦ÊÇ$\frac{3}{4}{m}_{1}g$£»·½ÏòˮƽÏò×ó£»
£¨3£©ÓûʹÎïÌåÒÒÔÚˮƽÃæÉϲ»»¬¶¯Í¬Ê±Éþ×Ó²»¶Ï£¬ÎïÌå¼×µÄÖÊÁ¿m1×î´ó²»Äܳ¬¹ý5.6kg£®
µãÆÀ ±¾ÌâÖ÷ÒªÊÇ¿¼²éÁ˹²µãÁ¦µÄƽºâÎÊÌ⣬½â´ð´ËÀàÎÊÌâµÄÒ»°ã²½ÖèÊÇ£ºÈ·¶¨Ñо¿¶ÔÏó¡¢½øÐÐÊÜÁ¦·ÖÎö¡¢ÀûÓÃƽÐÐËıßÐη¨Ôò½øÐÐÁ¦µÄºÏ³É»òÕßÊÇÕý½»·Ö½â·¨½øÐÐÁ¦µÄ·Ö½â£¬È»ºóÔÚ×ø±êÖáÉϽ¨Á¢Æ½ºâ·½³Ì½øÐнâ´ð£®
A£® | ת̨¶ÔBµÄĦ²ÁÁ¦Ò»¶¨Îª3¦Ìmg | |
B£® | AÓëת̨¼äµÄĦ²ÁÁ¦Ð¡ÓÚBÓëת̨¼äµÄĦ²ÁÁ¦ | |
C£® | ת̨µÄ½ÇËÙ¶ÈÒ»¶¨Âú×ã¦Ø¡Ü$\sqrt{\frac{¦Ìg}{3r}}$ | |
D£® | ת̨µÄ½ÇËÙ¶ÈÒ»¶¨Âú×ã¦Ø¡Ü$\sqrt{\frac{2¦Ìg}{3r}}$ |
A£® | 30kg•m/s | B£® | 5.7¡Á102kg•m/s | C£® | 6.0¡Á102kg•m/s | D£® | 6.3¡Á102kg•m/s |
A£® | Ë®Á÷ËÙ¶ÈÔ½´ó£¬Ë®·Ö×ÓµÄÈÈÔ˶¯Ô½¾çÁÒ | |
B£® | Ë®Äý½á³É±ùºó£¬Ë®·Ö×ÓµÄÈÈÔ˶¯Í£Ö¹ | |
C£® | Ë®µÄζÈÔ½¸ß£¬Ë®·Ö×ÓµÄÈÈÔ˶¯Ô½¾çÁÒ | |
D£® | Ë®µÄζÈÉý¸ß£¬Ã¿Ò»¸öË®·Ö×ÓµÄÔ˶¯ËÙÂʶ¼»áÔö´ó |
A£® | 2F | B£® | 0 | C£® | F | D£® | $\frac{F}{2}$ |
A£® | aºÍbµÄÏòÐļÓËٶȶ¼µÈÓÚÖØÁ¦¼ÓËÙ¶Èg | |
B£® | aµÄ½ÇËÙ¶È×î´ó | |
C£® | c¾àÀëµØÃæµÄ¸ß¶È²»ÊÇһȷ¶¨Öµ | |
D£® | dÊÇÈý¿ÅÎÀÐÇÖж¯ÄÜ×îС£¬»úеÄÜ×î´óµÄ |