Question

17£®ÔÚ¡°²âС³µµÄƽ¾ùËٶȡ±µÄʵÑéÖУ¬Éè¼ÆÁËÈçͼËùʾµÄʵÑé×°Öã¬Ð¡³µ´Ó´ø¿Ì¶ÈµÄбÃ涥¶ËÓɾ²Ö¹Ï»¬£¬Í¼ÖеÄԲȦÊÇС³µµ½´ïA¡¢B¡¢CÈý´¦Ê±µç×Ó±íµÄÏÔʾ£¨Êý×Ö·Ö±ð±íʾ¡°Ð¡Ê±£º·Ö£ºÃ롱£©
£¨1£©¸ÃʵÑé²âС³µÆ½¾ùËٶȵÄʵÑéÔ­ÀíÊÇv=$\frac{s}{t}$£®
£¨2£©ÊµÑéÖÐӦʹбÃæƶȽÏС£¨Ìî¡°´ó¡¢Ð¡¡±£©£¬ÆäÄ¿µÄÊÇ£º±ãÓÚ²âÁ¿Ê±¼ä£®
£¨3£©Èôs₂µÄ·³ÌÕýºÃÊÇÈ«²¿Â·³ÌµÄÒ»°ë£¬Ð¡³µÍ¨¹ýÉÏ°ë¶Î·³ÌABµÄƽ¾ùËÙ¶Èv_AB=0.2m/s£®Ð¡³µÍ¨¹ýÏ°ë¶Î·³ÌBCµÄƽ¾ùËÙ¶ÈV_BC=0.3m/s£¬Ð¡³µÍ¨¹ýAC·³ÌµÄƽ¾ùËÙ¶Èv_AC=0.24m/s£®
£¨4£©ÊµÑéʱ£¬ÒªÇó¼Æʱ׼ȷ£¬Èç¹ûijͬѧÔÚС³µ¹ýÁËAµã²Å¿ªÊ¼¼Æʱ£¬Ôò»áʹËù²âAC¶ÎµÄƽ¾ùËÙ¶Èv_ACÆ«´ó£¨Ñ¡Ìî¡°´ó¡±»ò¡°Ð¡¡±£©£®

Answer 1

·ÖÎö £¨1£©¹«Ê½v=$\frac{s}{t}$¼ÈÄÜÓÃÓÚÔÈËÙÖ±ÏßÔ˶¯ÇóËٶȣ¬ÓÖÄÜÓÃÓÚ±äËÙÖ±ÏßÔ˶¯Çóƽ¾ùËٶȣ®
£¨2£©Ð±ÃæÇã½ÇԽС£¬Ð¡³µËٶȱ仯ԽÂý£¬Ð¡³µÔ˶¯Ê±¼äÔ½³¤£¬±ãÓÚʱ¼äµÄ²âÁ¿£®
£¨3£©ÓÉͼ¶Á³öС³µÍ¨¹ýÈ«¹ý³Ì×ߵķ³ÌºÍËùÓõÄʱ¼ä£¬ÀûÓÃËٶȹ«Ê½ÇóС³µÍ¨¹ýÈ«¹ý³ÌµÄƽ¾ùËٶȣ»ÔÙ¶Á³ö×ßs₂µÄ·³ÌÓõÄʱ¼ä£¬ÀûÓÃËٶȹ«Ê½ÇóС³µÍ¨¹ýÉÏ°ë¶Î·³ÌµÄƽ¾ùËٶȣ»
£¨4£©Èç¹ûÈÃС³µ¹ýÁËAµãºó²Å¿ªÊ¼¼Æʱ£¬¼Æʱ¹ýÍí£¬Ê¹Ëù¼Æʱ¼äƫС£»¸ù¾Ýv=$\frac{s}{t}$£¬ÏàͬµÄ·³Ì£¬²âÁ¿Ê±¼äС£¬Ôò¼ÆËãµÄËÙ¶ÈÆ«´ó£»

½â´ð ½â£º
£¨1£©¸ÃʵÑé²âС³µÆ½¾ùËٶȵÄʵÑéÔ­ÀíÊÇv=$\frac{s}{t}$£®
£¨2£©Ð±ÃæƶÈÔ½´ó£¬Ð¡³µÑØбÃæÏòϼÓËÙÔ˶¯Ô½¿ì£¬¹ýijµãµÄʱ¼ä»áÔ½¶Ì£¬¼Æʱ»áÔ½À§ÄÑ£¬ËùÒÔΪʹ¼Æʱ·½±ã£¬Ð±ÃæƶÈÓ¦½ÏС£®
£¨3£©ÓÉͼ֪£¬ÓÉͼ֪£¬Ð¡³µÍ¨¹ýÈ«¹ý³Ì×ߵķ³Ìs₁=120cm=1.2m£¬ËùÓõÄʱ¼ät₁=5s£¬
С³µÍ¨¹ýÉÏ°ë³Ì×ߵķ³Ìs₂=$\frac{1}{2}$s₁=$\frac{1}{2}$¡Á120cm=60cm=0.6m£¬ËùÓõÄʱ¼ät₂=3s£¬Ð¡³µÍ¨¹ýÏ°ë³Ì×ߵķ³Ìs₃=$\frac{1}{2}$s₁=$\frac{1}{2}$¡Á120cm=60cm=0.6m£¬ËùÓõÄʱ¼ät₃=2s£¬
v_AB=$\frac{{s}_{2}}{{t}_{2}}$=$\frac{0.6m}{3s}$=0.2m/s£»
v_BC=$\frac{{s}_{3}}{{t}_{3}}$=$\frac{0.6m}{2s}$=0.3m/s£»
ÓÉv_AC=$\frac{{s}_{1}}{{t}_{1}}$=$\frac{1.2m}{5s}$=0.24m/s£»
£¨4£©¼ÆʱÍí£¬Ëù¼Æʱ¼äƫС£¬Óù«Ê½v=$\frac{s}{t}$Ëã³öµÄËÙ¶ÈÆ«´ó£®
¹Ê´ð°¸Îª£º£¨1£©v=$\frac{s}{t}$£»£¨2£©Ð¡£»±ãÓÚ²âÁ¿Ê±¼ä£»£¨3£©0.24£»0.2£»£¨4£©´ó£®

µãÆÀ ¡°²âС³µµÄƽ¾ùËٶȡ±µÄʵÑ飬һ¶¨Ñ§»á¶Á³ö·³ÌºÍʱ¼ä£¬°´Æ½¾ùËٶȵĶ¨Òå´úÈëv=$\frac{s}{t}$Ëã³öƽ¾ùËٶȣ®