Question

18£®Í¬Ñ§Éè¼ÆÁËÒ»¸öÓôòµã¼ÆʱÆ÷ÑéÖ¤¶¯Á¿Êغ㶨ÂɵÄʵÑ飺ÔÚС³µAµÄÇ°¶ËÕ³ÓÐÏðƤÄ࣬Íƶ¯Ð¡³µAʹ֮×öÔÈËÙÔ˶¯£®È»ºóÓëÔ­À´¾²Ö¹ÔÚÇ°·½µÄС³µBÏàÅö²¢Õ³ºÏ³ÉÒ»Ì壬¼ÌÐø×öÔÈËÙÔ˶¯£¬Èçͼ1Ëùʾ£®ÔÚС³µAºóÁ¬×ÅÖ½´ø£¬µçԴƵÂÊΪ50Hz£¬³¤Ä¾°å¹â»¬£®
£¨1£©ÈôÒѵõ½´òµãÖ½´øÈçͼ2£¬AΪÔ˶¯ÆðʼµÄµÚÒ»µã£¬ÔòӦѡBC¶ÎÀ´¼ÆËãС³µAµÄÅöÇ°Ëٶȣ¬Ó¦Ñ¡DE¶ÎÀ´¼ÆËãС³µAºÍС³µBÅöºóµÄ¹²Í¬Ëٶȣ®
£¨2£©ÒѲâµÃС³µAµÄÖÊÁ¿m₁=0.040kg£¬Ð¡³µBµÄÖÊÁ¿m₂=0.020kg£®ÓÉÒÔÉϲâÁ¿½á¹û¿ÉµÃ£ºÅöÇ°×ܶ¯Á¿Îª0.042kg•m/s£¬Åöºó×ܶ¯Á¿Îª0.0417kg•m/s£®

Answer 1

·ÖÎö С³µ×öÔÈËÙÖ±ÏßÔ˶¯Ê±£¬ÔÚÏàµÈʱ¼äÄÚС³µµÄλÒÆÏàµÈ£¬·ÖÎöÖ½´ø£¬¸ù¾ÝÖ½´ø·ÖÎöÇó½âËٶȣ¬ÔÙ¸ù¾Ý¶¯Á¿µÄ¶¨Òå·ÖÎöÇó½âÅöײǰºóµÄ¶¯Á¿´óС£®

½â´ð ½â£º£¨1£©Íƶ¯Ð¡³µÓɾ²Ö¹¿ªÊ¼Ô˶¯£¬¹ÊС³µÓиö¼ÓËÙ¹ý³Ì£¬ÔÚÅöײǰ×öÔÈËÙÖ±ÏßÔ˶¯£¬¼´ÔÚÏàͬµÄʱ¼äÄÚͨ¹ýµÄλÒÆÏàͬ£¬¹ÊBC¶ÎΪÔÈËÙÔ˶¯µÄ½×¶Î£¬¹ÊÑ¡BC¼ÆËãÅöÇ°µÄËٶȣ»
Åöײ¹ý³ÌÊÇÒ»¸ö±äËÙÔ˶¯µÄ¹ý³Ì£¬¶øAºÍBÅöºóµÄ¹²Í¬Ô˶¯Ê±×öÔÈËÙÖ±ÏßÔ˶¯£¬¹ÊÔÚÏàͬµÄʱ¼äÄÚͨ¹ýÏàͬµÄλÒÆ£¬¹ÊӦѡDE¶ÎÀ´¼ÆËãÅöºó¹²Í¬µÄËٶȣ®
£¨2£©ÓÉͼ¿ÉÖª£¬BC=10.50cm=0.1050m£»
DE=6.95cm=0.0695m£»
AÅöÇ°µÄËٶȣºv₁=$\frac{BC}{t}$=$\frac{0.1050}{5¡Á0.02}$=1.05m/s
Åöºó¹²Í¬Ëٶȣºv₂=$\frac{DE}{t}$=$\frac{0.0695}{5¡Á0.02}$=0.695m/s
ÅöÇ°×ܶ¯Á¿£ºP₁=m₁v₁=0.04¡Á1.05=0.042kg£®m/s
ÅöºóµÄ×ܶ¯Á¿£ºP₂=£¨m₁+m₂£©v₂=0.06¡Á0.695=0.0417kg£®m/s
¹Ê´ð°¸Îª£º£¨1£©BC  DE  £¨2£©0.042   0.04l7

µãÆÀ ±¾Ì⿼²éÑéÖ¤¶¯Á¿Êغ㶨ÂɵÄʵÑéÔ­Àí£¬Òª×¢Òâ½â¾ö±¾ÌâµÄ¹Ø¼üÖªµÀAÓëBÅöºó£¬ËٶȼõС£¬»áͨ¹ýÖ½´øÇó½âËٶȵĴóС£»ÔÙͨ¹ýÅöײǰºóµÄ¶¯Á¿´óС¹ØϵÑéÖ¤¶¯Á¿ÊÇ·ñÏàµÈ¼´¿É£®