ÌâÄ¿ÄÚÈÝ
¡¾ÌâÄ¿¡¿¾²Ö¹ÔÚˮƽÃæÉϵÄA¡¢BÁ½¸öÎïÌåͨ¹ýÒ»¸ùÀÖ±µÄÇáÉþÏàÁ¬£¬ÈçͼËùʾ¡£ÇáÉþ³¤L=1m£¬³ÐÊܵÄ×î´óÀÁ¦Îª8N£¬AµÄÖÊÁ¿m1=2kg£¬BµÄÖÊÁ¿m2=8kg£¬A¡¢BÓëˮƽÃæ¼äµÄ¶¯Ä¦²ÁÒòÊý¦Ì=0.2£¬ÏÖÓÃÒ»Öð½¥Ôö´óµÄˮƽÁ¦F×÷ÓÃÔÚBÉÏ£¬Ê¹A¡¢BÏòÓÒÔ˶¯£¬µ±FÔö´óµ½Ä³Ò»ÖµÊ±£¬ÇáÉþ¸ÕºÃ±»À¶Ï£¨gÈ¡10m/s2£©¡£
(1)ÇóÉþ¸Õ±»À¶ÏʱFµÄ´óС¡£
(2)ÈôÉþ¸Õ±»À¶Ïʱ£¬A¡¢BµÄËÙ¶ÈΪ2m/s£¬±£³Ö´ËʱµÄF´óС²»±ä£¬µ±A¾²Ö¹Ê±£¬A¡¢B¼äµÄ¾àÀëΪ¶àÉÙ?
¡¾´ð°¸¡¿£¨1£©40N £¨2£©3.5 m
¡¾½âÎö¡¿
(1)ÉèÉþ¸ÕÒª±»À¶Ïʱ²úÉúµÄÀÁ¦ÎªFT£¬¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉ,
¶ÔAÎïÌåÓÐ
FT-¦Ìm1g=m1a
´úÈëÊýÖµµÃ
a=2m/s2
¶ÔA¡¢BÕûÌåÓУº
F-¦Ì£¨m1+m2£©g=£¨m1+m2£©a
´úÈëÊýÖµµÃ
F=40N
(2)ÉèÉþ¶Ïºó£¬AµÄ¼ÓËÙ¶ÈΪa1£¬BµÄ¼ÓËÙ¶ÈΪa2£¬Ôò
a1==2m/s2
a2==3m/s2
AÍ£ÏÂÀ´µÄʱ¼äΪt£¬Ôò
t==1s
AµÄλÒÆΪx1£¬Ôò
x1==1m
BµÄλÒÆΪx2£¬Ôò
x2=vt+a2t2=3.5m
A¸Õ¾²Ö¹Ê±£¬A¡¢B¼ä¾àÀëΪ
¦¤x=x2+L-x1=3.5m