ÌâÄ¿ÄÚÈÝ
20£®ÏàͬµÄÁ½Îï¿éA¡¢B¾ùΪm£¬ÓÃÇᵯ»ÉÁ¬½Óºó·ÅÔÚˮƽÃæÉÏ£¬¶ÔBÊ©¼ÓˮƽÀÁ¦F£¬Îȶ¨ºóA¡¢BÒÔÏàͬ¼ÓËٶȺÍÏàͬËÙ¶ÈÔÚˮƽÃæÉÏÔ˶¯£¬²âµÃ´Ëʱµ¯»É³¤Îªl1£»Èô³·È¥ÀÁ¦F£¬»»³É´óСÈÔΪFµÄˮƽÍÆÁ¦ÍÆA£¬Îȶ¨ºóµ¯»É³¤Îªl2£¬ÔòÏÂÁÐÅжÏÕýÈ·µÄÊÇ£¨¡¡¡¡£©A£® | µ¯»ÉµÄÔ³¤Îª$\frac{{{l_1}+{l_2}}}{2}$ | B£® | Á½´Î×÷Óõ¯»ÉµÄÐαäÁ¿²»ÏàµÈ | ||
C£® | µ¯»ÉµÄ¾¢¶ÈϵÊýΪ$\frac{F}{{{l_1}-{l_2}}}$ | D£® | Îȶ¨Ê±Á½Îï¿éµÄ¼ÓËÙ¶ÈΪ$\frac{F}{2m}$ |
·ÖÎö ¶ÔÕûÌå·ÖÎö£¬¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉÇó³öÕûÌåµÄ¼ÓËٶȣ¬·Ö±ð¶ÔµÚÒ»ÖÖÇé¿öµÄAºÍµÚ¶þÖÖÇé¿öµÄB·ÖÎö£¬ÔËÓÃÅ£¶ÙµÚ¶þ¶¨ÂÉÁªÁ¢Çó³öµ¯»ÉµÄÔ³¤ºÍ¾¢¶ÈϵÊý£®´Ó¶øÇó³öµ¯»ÉµÄÐαäÁ¿£®
½â´ð ½â£ºÒÔA¡¢BÕûÌåΪÑо¿¶ÔÏ󣬸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉÖª£¬Á½ÖÖÇé¿öϵļÓËÙ¶ÈÏàµÈ
F-¦Ì•2mg=2ma
µÃ$a=\frac{F}{2m}-¦Ìg$£¬¹ÊD´íÎó£»
É赯»ÉµÄÔ³¤Îª${l}_{0}^{\;}$£¬¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨Âɵãº
µÚÒ»ÖÖÇé¿ö£º¶ÔA$k£¨{l}_{1}^{\;}-{l}_{0}^{\;}£©-¦Ìmg=ma$¢Ù
µÚ¶þÖÖÇé¿ö£º¶ÔB$k£¨{l}_{0}^{\;}-{l}_{2}^{\;}£©-¦Ìmg=ma$¢Ú
ÓÉ¢Ù¢ÚµÃ${l}_{0}^{\;}=\frac{{l}_{1}^{\;}+{l}_{2}^{\;}}{2}$£¬$k=\frac{F}{{l}_{1}^{\;}-{l}_{2}^{\;}}$£¬¹ÊACÕýÈ·£»
µÚÒ»´Î×÷Óõ¯»ÉµÄÐαäÁ¿$¡÷{x}_{1}^{\;}={l}_{1}^{\;}-{l}_{0}^{\;}=\frac{{l}_{1}^{\;}-{l}_{2}^{\;}}{2}$
µÚ¶þ´Î×÷Óõ¯»ÉµÄÐαäÁ¿$¡÷{x}_{2}^{\;}={l}_{0}^{\;}-{l}_{2}^{\;}=\frac{{l}_{1}^{\;}-{l}_{2}^{\;}}{2}$£¬¹ÊB´íÎó£»
¹ÊÑ¡£ºAC
µãÆÀ ±¾Ì⿼²éÁËÅ£¶ÙµÚ¶þ¶¨Âɺͺú¿Ë¶¨ÂɵÄ×ÛºÏÔËÓ㬹ؼüÑ¡ÔñºÃÑо¿µÄ¶ÔÏó£¬ÔËÓÃÅ£¶ÙµÚ¶þ¶¨ÂɽøÐÐÇó½â£¬ÕÆÎÕÕûÌå·¨ºÍ¸ôÀë·¨µÄÔËÓã®
A£® | ÈôС³µ²»¹Ì¶¨£¬ÔòÒÔС³µºÍСÇòΪϵͳ¶¯Á¿Êغã | |
B£® | ÒÔС³µºÍСÇòΪϵͳ»úеÄܲ»Êغã | |
C£® | ÈôС³µ²»¹Ì¶¨£¬ÔòСÇòÔٻص½µÈ¸ßλÖÃʱºÍÔÀ´³ö·¢µãÏà¾à$\frac{2ML}{M+m}$ | |
D£® | ÈôС³µ²»¹Ì¶¨£¬ÔòСÇòÔٻص½µÈ¸ßλÖÃʱºÍÔÀ´³ö·¢µãÏà¾à$\frac{ML}{M+m}$ |
A£® | 0¡«5 sÖ±Éý»úÉÏÉý¹ý³ÌÖмÓËٶȲ»±ä | |
B£® | 5¡«15 sÖ±Éý»úÍ£ÔÚ¿ÕÖ⻶¯ | |
C£® | t=20 sʱֱÉý»úµÄËٶȡ¢¼ÓËٶȶ¼ÎªÁã | |
D£® | 20¡«25 sÖ±Éý»úÊúÖ±ÏòÏÂÔ˶¯ |
A£® | ¼ÓËٵľÍÊÇÔö¼Ó | |
B£® | ¼ÓËٶȵĴóС·´Ó³ÁËËٶȱ仯µÄ´óС | |
C£® | ¼ÓËٶȵĴóС·´Ó³ÁËËٶȱ仯µÄ¿ìÂý | |
D£® | ¼ÓËٶȵĴóС·´Ó³ÁËËٶȶÔʱ¼äµÄ±ä»¯ÂʵĴóС |
A£® | EA£¼EB£»ϕA£¼ϕB | B£® | EA£¼EB£»ϕA£¾ϕB | C£® | EA£¾EB£»ϕA£¼ϕB | D£® | EA£¾EB£»ϕA£¾ϕB |
A£® | I1ÑØÄæʱÕë·½Ïò£¬I2ÑØ˳ʱÕë·½Ïò | |
B£® | I2ÑØ˳ʱÕë·½Ïò£¬I3ÑØÄæʱÕë·½Ïò | |
C£® | F1·½ÏòÖ¸ÏòÔ²ÐÄ£¬F2·½ÏòÖ¸ÏòÔ²ÐÄ | |
D£® | F2·½Ïò±³ÀëÔ²ÐÄÏòÍ⣬F3·½ÏòÖ¸ÏòÔ²ÐÄ |