Question

£¨19·Ö£©ÈçͼËùʾ£¬M₁N₁¡¢M₂N₂ÊÇÁ½¸ù´¦ÓÚͬһˮƽÃæÄÚµÄƽÐе¼¹ì£¬µ¼¹ì¼ä¾àÀëÊÇd=0.5m£¬µ¼¹ì×ó¶Ë½ÓÓж¨Öµµç×èR=2¦¸£¬ÖÊÁ¿Îªm=0.1kgµÄ»¬¿é´¹Ö±ÓÚµ¼¹ì£¬¿ÉÔÚµ¼¹ìÉÏ×óÓÒ»¬¶¯²¢Óëµ¼¹ìÓÐÁ¼ºÃµÄ½Ó´¥£¬»¬¶¯¹ý³ÌÖл¬¿éÓëµ¼¹ì¼äµÄĦ²ÁÁ¦ºãΪf=1N£¬»¬¿éÓþøԵϸÏßÓëÖÊÁ¿ÎªM=0.2kgµÄÖØÎïÁ¬½Ó£¬Ï¸Ïß¿ç¹ý¹â»¬µÄ¶¨»¬ÂÖ£¬Õû¸ö×°Ö÷ÅÔÚÊúÖ±ÏòÉϵÄÔÈÇ¿´Å³¡ÖУ¬´Å³¡µÄ´Å¸ÐӦǿ¶ÈÊÇB=2T£¬½«»¬¿éÓɾ²Ö¹ÊÍ·Å¡£Éèµ¼¹ì×ã¹»³¤£¬´Å³¡×ã¹»´ó£¬MδÂäµØ£¬ÇÒ²»¼Æµ¼¹ìºÍ»¬¿éµÄµç×è¡£g=10m/s² £¬Çó£º

(1£©»¬¿éÄÜ»ñµÃµÄ×î´óËٶȠ 

(2£©»¬¿éµÄ¼ÓËÙ¶ÈΪa=2m/s²Ê±µÄËÙ¶È

(3£©É軬¿é´Ó¿ªÊ¼Ô˶¯µ½»ñµÃ×î´óËٶȵĹý³ÌÖУ¬µçÁ÷ÔÚµç×èRÉÏËù ×öµÄµç¹¦ÊÇw=0.8J£¬Çó´Ë¹ý³ÌÖл¬¿é»¬¶¯µÄ¾àÀë

 

Answer 1

£¨1£©Vm=2m/s£¨2£©0.8m/s£¨3£©1.4m

½âÎö:£¨1£©Mg=f+BId   ¢Ù ---------------------------------------------------£¨2·Ö£©

I=E/R       ¢Ú ---------------------------------------------------£¨2·Ö£©

E=BdVm     ¢Û ---------------------------------------------------£¨2·Ö£©

ÁªÁ¢¢Ù¢Ú¢Û½âÖ®²¢´úÈ붯Äܱí´ïʽ£ºVm=2m/s  -----------£¨2·Ö£©

 (2£©

Mg-f-BId=(M+m)a    ¢Ü-----------------------------------------£¨3·Ö£©

ÁªÁ¢¢Ú¢Û¢Ü½âÖ®£ºV=R [Mg-f-(M+m)a]/B2d2 =0.8m/s  ------------------£¨2·Ö£©

(3£©

Mgx-fx-w=£¨m+M£©Vm2/2 ----------------------------------------£¨3·Ö£©

 x={£¨m+M£©[(Mg-f)R]2/2B4d4+w}/(Mg-f)=1.4m  ---------------£¨3·Ö£©