Question

18£®²âС³µµÄƽ¾ùËٶȣ®

?£¨1£©²âƽ¾ùËÙ¶ÈÐèÒªµÄ²âÁ¿¹¤¾ßÊǿ̶ȳߺÍÃë±í£¬¸ÃʵÑéÒÀ¾ÝµÄÔ­ÀíÊÇv=$\frac{s}{t}$£®

´ÎÊý	·³Ì£¨m£©	Ô˶¯Ê±¼ä£¨s£©	ƽ¾ùËٶȣ¨m/s£©
È«³Ì	1.6	5.0	0.32
Ç°°ë³Ì	0.8	2.8
ºó°ë³Ì

£¨2£©ÈçͼËùʾ£¬Ð±Ã泤1.6m£¬²âµÃС³µ´ÓбÃ涥¶ËÔ˶¯µ½µ×¶ËËùÓõÄʱ¼äÊÇ5s£®Èç¹ûÔÚбÃæµÄÖеã×°ÉϽðÊôƬ£¬²âµÃС³µ´ÓбÃ涥¶ËÔ˶¯µ½½ðÊôƬµÄʱ¼äΪ2.8s£®Ç뽫²âÁ¿Êý¾ÝÌîÈë±íÖУ¬²¢¼ÆËã³öС³µÍ¨¹ýÉÏ¡¢Ï°ë¶ÎµÄƽ¾ùËÙ¶ÈV₁=0.29m/s ºÍV₂=0.36m/s£®£¨±£ÁôÁ½Î»Ð¡Êý£©
£¨3£©Ð¡³µ´ÓбÃ涥¶ËÔ˶¯µ½µ×¶Ë¹ý³ÌÖУ¬Ð¡³µ×öµÄÊDZäËÙÖ±ÏßÔ˶¯£¨Ìî¡°ÔÈËÙ¡±»ò¡°±äËÙ¡±£©£®

Answer 1

·ÖÎö £¨1£©²âÁ¿Ð¡³µÔÚбÃæÉϵÄƽ¾ùËٶȣ¬ÐèÒª²âÁ¿Ð±Ã泤¶ÈºÍÔ˶¯Ê±¼ä£¬ÀûÓÃËٶȹ«Ê½v=$\frac{s}{t}$Çó½â£®
£¨2£©¸ù¾ÝÌâÒâµÃ³öºó°ë³ÌµÄ·³ÌºÍС³µÍ¨¹ýºó°ë³ÌËùÓÃʱ¼ä£¬ÀûÓÃv=$\frac{s}{t}$¼ÆËãС³µÇ°°ë³ÌºÍºó°ë³ÌµÄËٶȴóС£»
£¨3£©±È½ÏС³µÔÚÉÏ°ë³ÌºÍÏ°ë³ÌµÄËٶȴóС£¬µÃ³öС³µ´ÓбÃ涥¶ËÔ˶¯µ½µ×¶Ë¹ý³ÌÖеÄÔ˶¯×´Ì¬£®

½â´ð ½â£º
£¨1£©²âÁ¿Ð¡³µÔÚбÃæÉϵÄƽ¾ùËٶȻù±¾Ô­ÀíÊÇv=$\frac{s}{t}$£¬ÐèÒª²âÁ¿Ð¡³µµÄÔ˶¯Â·³ÌºÍËùÓÃʱ¼ä£¬ËùÒÔÐèÒªµÄ²âÁ¿¹¤¾ßÊǿ̶ȳߺÍÃë±í£®
£¨2£©Ð±Ã泤1.6m£¬²âµÃС³µ´ÓбÃ涥¶ËÔ˶¯µ½µ×¶ËËùÓõÄʱ¼äÊÇ5s£®
Ôòºó°ë³ÌµÄ·³Ìs₂=$\frac{1}{2}$s=$\frac{1}{2}$¡Á1.6m=0.8m£¬ºó°ë³ÌµÄʱ¼ät₂=5.0s-2.8s=2.2s£¬
ÉÏ°ë³ÌµÄƽ¾ùËٶȣºv₁=$\frac{{s}_{1}}{{t}_{1}}$=$\frac{0.8m}{2.8s}$¡Ö0.29m/s£¬
Ï°ë³ÌµÄƽ¾ùËٶȣºv₂=$\frac{{s}_{2}}{{t}_{2}}$=$\frac{0.8m}{2.2s}$¡Ö0.36m/s£»
£¨3£©Í¨¹ý£¨2£©µÄ¼ÆËã¿ÉÖª£¬Ð¡³µÔÚÉÏ°ë³ÌºÍÏ°ë³ÌµÄËٶȹØϵΪv₁£¼v₂£¬
ËùÒÔ£¬Ð¡³µ´ÓбÃ涥¶ËÔ˶¯µ½µ×¶Ë¹ý³ÌÖУ¬Ð¡³µ×öµÄÊDZäËÙÖ±ÏßÔ˶¯£®
¹Ê´ð°¸Îª£º£¨1£©¿Ì¶È³ß£»Ãë±í£»v=$\frac{s}{t}$£»£¨2£©0.29m/s£»0.36m/s£»£¨3£©±äËÙ£®

µãÆÀ ±¾Ì⿼²é¡°²âС³µµÄƽ¾ùËٶȡ±µÄʵÑ飬һ¶¨Ñ§»á¶Á³ö·³ÌºÍʱ¼ä£¬°´Æ½¾ùËٶȵĶ¨Òå´úÈëv=$\frac{s}{t}$Çó³öƽ¾ùËٶȣ®