ÌâÄ¿ÄÚÈÝ
É̳¡¹¤×÷ÈËÔ±À×ÅÖÊÁ¿m=20kgµÄľÏäÑØˮƽµØÃæÔ˶¯£®ÈôÓÃF1=100NµÄˮƽÁ¦ÀľÏ䣬ľÏäÇ¡ºÃ×öÔÈËÙÖ±ÏßÔ˶¯£»ÏÖ¸ÄÓÃF2=150N¡¢Óëˮƽ·½Ïò³É53¡ãбÏòÉϵÄÀÁ¦×÷ÓÃÓÚ¾²Ö¹µÄľÏäÉÏ£¬ÈçͼËùʾ£®ÒÑÖªsin53¡ã=0.80£¬cos53¡ã=0.60£¬È¡ÖØÁ¦¼ÓËÙ¶Èg=10m/s2£®
Ç󣺣¨1£©Ä¾ÏäÓëµØÃæÖ®¼äµÄ¶¯Ä¦²ÁÒòÊý£»
£¨2£©F2×÷ÓÃÔÚľÏäÉÏʱ£¬Ä¾ÏäÔ˶¯µÄ¼ÓËٶȴóС£»
£¨3£©F2×÷ÓÃÔÚľÏäÉÏ4.0sʱ¼äÄÚľÏäÒƶ¯µÄ¾àÀ룮
Ç󣺣¨1£©Ä¾ÏäÓëµØÃæÖ®¼äµÄ¶¯Ä¦²ÁÒòÊý£»
£¨2£©F2×÷ÓÃÔÚľÏäÉÏʱ£¬Ä¾ÏäÔ˶¯µÄ¼ÓËٶȴóС£»
£¨3£©F2×÷ÓÃÔÚľÏäÉÏ4.0sʱ¼äÄÚľÏäÒƶ¯µÄ¾àÀ룮
·ÖÎö£º£¨1£©ÓÃF1=100NµÄˮƽÁ¦ÀľÏ䣬ľÏäÇ¡ºÃ×öÔÈËÙÖ±ÏßÔ˶¯£¬ÓÉ´Ë¿ÉÖªÀÁ¦ºÍĦ²ÁÁ¦ÏàµÈ£¬´Ó¶ø¿ÉÒÔÇó³ö¶¯Ä¦²ÁÒòÊý£»
£¨2£©¶ÔÎïÌåÊÜÁ¦·ÖÎö£¬ÓÉÅ£¶ÙµÚ¶þ¶¨ÂÉ¿ÉÒÔÇóµÃ¼ÓËٶȵĴóС£»
£¨3£©Ä¾Ïä×öÔȼÓËÙÔ˶¯£¬ÓÉλÒƹ«Ê½¿ÉÒÔÇóµÃľÏäµÄλÒÆ£®
£¨2£©¶ÔÎïÌåÊÜÁ¦·ÖÎö£¬ÓÉÅ£¶ÙµÚ¶þ¶¨ÂÉ¿ÉÒÔÇóµÃ¼ÓËٶȵĴóС£»
£¨3£©Ä¾Ïä×öÔȼÓËÙÔ˶¯£¬ÓÉλÒƹ«Ê½¿ÉÒÔÇóµÃľÏäµÄλÒÆ£®
½â´ð£º½â£º£¨1£©ÓÉÓÚľÏäÔÚˮƽÀÁ¦ÏÂÔÈËÙÔ˶¯£¬¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉ£¬
F1-¦Ìmg=0
½âµÃ£º¦Ì=
=0.5
£¨2£©½«F2ÑØ×ÅˮƽÓëÊúÖ±·½Ïò·Ö½â£¬F2ÑØˮƽºÍÊúÖ±·½ÏòµÄ·ÖÁ¿·Ö±ðΪ
F2x=F2cos53¡ã F2y=F2sin53¡ã
ľÏäÊܵ½Ë®Æ½µØÃæµÄÖ§³ÖÁ¦ FN=mg-F2y
¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉ£¬F2x-¦ÌFN=ma
½âµÃľÏäÔ˶¯µÄ¼ÓËٶȴóСΪ a=2.5 m/s2
£¨3£©¸ù¾ÝÔ˶¯Ñ§¹«Ê½£¬
ľÏäµÄλÒÆ X=
at2=20m£®
´ð£º£¨1£©Ä¾ÏäÓëµØÃæÖ®¼äµÄ¶¯Ä¦²ÁÒòÊýΪ0.5£»
£¨2£©F2×÷ÓÃÔÚľÏäÉÏʱ£¬Ä¾ÏäÔ˶¯µÄ¼ÓËٶȴóСΪ2.5 m/s2£»
£¨3£©F2×÷ÓÃÔÚľÏäÉÏ4.0sʱ¼äÄÚľÏäÒƶ¯µÄ¾àÀëÊÇ20m£®
F1-¦Ìmg=0
½âµÃ£º¦Ì=
F1 |
mg |
£¨2£©½«F2ÑØ×ÅˮƽÓëÊúÖ±·½Ïò·Ö½â£¬F2ÑØˮƽºÍÊúÖ±·½ÏòµÄ·ÖÁ¿·Ö±ðΪ
F2x=F2cos53¡ã F2y=F2sin53¡ã
ľÏäÊܵ½Ë®Æ½µØÃæµÄÖ§³ÖÁ¦ FN=mg-F2y
¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉ£¬F2x-¦ÌFN=ma
½âµÃľÏäÔ˶¯µÄ¼ÓËٶȴóСΪ a=2.5 m/s2
£¨3£©¸ù¾ÝÔ˶¯Ñ§¹«Ê½£¬
ľÏäµÄλÒÆ X=
1 |
2 |
´ð£º£¨1£©Ä¾ÏäÓëµØÃæÖ®¼äµÄ¶¯Ä¦²ÁÒòÊýΪ0.5£»
£¨2£©F2×÷ÓÃÔÚľÏäÉÏʱ£¬Ä¾ÏäÔ˶¯µÄ¼ÓËٶȴóСΪ2.5 m/s2£»
£¨3£©F2×÷ÓÃÔÚľÏäÉÏ4.0sʱ¼äÄÚľÏäÒƶ¯µÄ¾àÀëÊÇ20m£®
µãÆÀ£º¸ù¾Ý¶þÁ¦Æ½ºâÇó³öĦ²ÁÁ¦µÄ´óС£¬Ö®ºóÎïÌå¾ÍÊÇÔȼÓËÙÖ±ÏßÔ˶¯£¬ÓÉÔȱäËÙÖ±ÏßÔ˶¯µÄ¹æÂÉÇó½â¼´¿É£¬±¾ÌâµÄÄѶȲ»´ó£®
Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿