Question

18£®¡°ÔÚÏàͬµÄÌõ¼þÏ£¬¹ö¶¯Ä¦²Á±È»¬¶¯Ä¦²ÁҪСµÃ¶à¡°£¬ÕâÊdzõÖÐѧϰĦ²ÁÁ¦Ê±µÃµ½µÄ½áÂÛ£®ÎªÁËÒ»²½Á˽âÕâÁ½¸öĦ²ÁÖ®¼äµÄ¹Øϵ£¬ÔÚʵÑéÊÒÀijͬѧÏÈ°ÑÒ»ÖÊÁ¿Îª200gµÄС³µËÄÂ̶ֹ¨£¬°ÑËü·ÅÔÚ¸ßΪ22.5cm£¬³¤92cmÇãб¹ìµÀÇ¡ÄÜÔÈËÙÏ»¬£»È»ºóËÉ¿ªËÄÂÖ£¬ÈÃËü´Ó¹ìµÀÉϾ²Ö¹ÊÍ·Å£¬²âµÃÆä´Ó¶¥¶ËÏ»¬µ½µ×¶ËʱµÄʱ¼äΪ1.0s£®£¨¼ÆËã½á¹û±£ÁôСÊýµãºóÁ½Î»£©Çó£º
£¨1£©Ð¡³µËÄÂ̶ֹ¨Ê±£¬ÔÚ¹ìµÀÉÏ»¬¶¯¹ý³ÌÖÐËùÊܵÄĦ²ÁÁ¦£»
£¨2£©Ð¡³µËÄÂÖ²»¹Ì¶¨£¬ÔÚ¹ìµÀÉϹöÔ˹ý³ÌÖеļÓËٶȣ»
£¨3£©Ð¡³µËÄÂ̶ֹ¨ºÍ²»¹Ì¶¨Ê±ËùÊܵÄĦ²ÁÁ¦Ö®±È£®

Answer 1

·ÖÎö £¨1£©Ð¡³µÔÈËÙÏ»¬£¬¸ù¾Ý¹²µãÁ¦Æ½ºâÇóµÃĦ²ÁÁ¦´óС£»
£¨2£©¸ù¾ÝλÒÆʱ¼ä¹«Ê½ÇóµÃ¼ÓËٶȣ»
£¨3£©¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉÇóµÃ¼ÓËÙÏ»¬Ê±Êܵ½µÄĦ²ÁÁ¦¼´¿ÉÇóµÃ±ÈÖµ£»

½â´ð ½â£º£¨1£©Ð¡³µÔÈËÙÔ˶¯£¬Ôòmgsin¦È-f=0
ÆäÖÐ$sin¦È=\frac{22.5}{92}=\frac{45}{184}$
½âµÃf=0.49N
£¨2£©¸ù¾ÝÔ˶¯Ñ§¹«Ê½¿ÉÖªx=$\frac{1}{2}a{t}^{2}$¿ÉµÃa=$\frac{2x}{{t}^{2}}=\frac{2¡Á0.92}{{1}^{2}}m/{s}^{2}=1.84m/{s}^{2}$
£¨3£©ÔÚ¼ÓËÙ¹ý³ÌÖУ¬¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉ¿ÉÖªmgsin¦È-f¡ä=ma£¬½âµÃf¡ä=mgsin¦È-ma=0.12N
¹Ê$\frac{f}{f¡ä}=\frac{0.49}{0.12}=\frac{49}{12}$
´ð£º£¨1£©Ð¡³µËÄÂ̶ֹ¨Ê±£¬ÔÚ¹ìµÀÉÏ»¬¶¯¹ý³ÌÖÐËùÊܵÄĦ²ÁÁ¦Îª0.49N£»
£¨2£©Ð¡³µËÄÂÖ²»¹Ì¶¨£¬ÔÚ¹ìµÀÉϹöÔ˹ý³ÌÖеļÓËÙ¶ÈΪ1.84m/s²£»
£¨3£©Ð¡³µËÄÂ̶ֹ¨ºÍ²»¹Ì¶¨Ê±ËùÊܵÄĦ²ÁÁ¦Ö®±ÈΪ49£º12

µãÆÀ ±¾ÌâÖ÷Òª¿¼²éÁ˹²µãÁ¦Æ½ºâºÍÅ£¶ÙµÚ¶þ¶¨ÂÉ£¬¼ÓËÙ¶ÈÊǽâÌâµÄÖмäÇÅÁº