Question

14£®ÔÚУÔ˶¯»á400m¾öÈüÖУ¬Ò»ÃûÔ˶¯Ô±ÔÚµ½´ïÖÕµãÇ°½øÈËÁ˳å´Ì½×¶Î£¬×îºó¸Ï³¬ÁËÇ°ÃæÒ»ÃûÔ˶¯Ô±»ñµÃµÚÒ»Ãû£®ÈôÔ˶¯Ô±³å´ÌʱµÄ³õËÙ¶ÈΪ7m/s£¬²¢ÒÔ0.5m/s²µÄ¼ÓËÙ¶ÈÔȼÓËÙ³å´ÌÁË6s£®Ôò£º
£¨1£©Ô˶¯Ô±¼ÓËÙ³å´ÌµÄÄ©ËÙ¶ÈΪ¶àÉÙ£¿
£¨2£©Ô˶¯Ô±¼ÓËٺ󣬽«±£³ÖÕâ¸öËٶȵ½´ïÖյ㣮ÒÑÖªËû¿ªÊ¼¼ÓËÙʱ¾àÖÕµã56m£¬ÄÇô£¬Õâ¸ö³å´Ì¼ÓËÙ¹ý³Ì½«Ê¹ËûµÄ³É¼¨Ìá¸ßÁ˶àÉÙ£¿
£¨3£©ÔÚÕâ¸öÔ˶¯Ô±¿ªÊ¼¼ÓËÙʱ£¬ÁíÒ»¸öÔ˶¯Ô±ÔÚËûÇ°Ãæ5m´¦£¬²¢Ò»Ö±ÒÔ7m/sµÄËÙ¶ÈÔÈËÙÇ°½ø£®µ±Õâ¸öÔ˶¯Ô±µ½´ïÖÕµãʱ£¬³¬¹ýÄÇÃûÔ˶¯Ô±¶àÔ¶£¿

Answer 1

·ÖÎö £¨1£©¸ù¾ÝÔȱäËÙÖ±ÏßÔ˶¯µÄËÙ¶Èʱ¼ä¹«Ê½Çó³öÔ˶¯Ô±¼ÓËÙ³å´ÌµÄÄ©ËٶȴóС£®
£¨2£©¸ù¾ÝÔ˶¯Ñ§¹«Ê½·Ö±ðÇó³ö²»¼ÓËٺͼÓËÙÔ˶¯¾­ÀúµÄʱ¼ä£¬´Ó¶øµÃ³ö¼ÓËÙ¹ý³ÌÌá¸ßµÄ³É¼¨£®
£¨3£©¸ù¾ÝÔ˶¯Ô±ÔÚÕâ¶Îʱ¼äÄÚµÄλÒÆ£¬µÃ³ö³¬Ô½µÄ¾àÀ룮

½â´ð ½â£º£¨1£©¸ù¾ÝËÙ¶Èʱ¼ä¹«Ê½µÃÔ˶¯Ô±¼ÓËÙ³å´ÌµÄÄ©ËÙ¶ÈΪ£ºv=v₀+at=7+0.5¡Á6m/s=10m/s£®
£¨2£©Èç¹û²»¼ÓËÙ£¬ËùÓÃʱ¼äΪ£º${t}_{1}=\frac{x}{{v}_{0}}=\frac{56}{7}s=8s$£¬
¼ÓËÙ¹ý³ÌµÄλÒÆΪ£º${x}_{1}={v}_{0}t+\frac{1}{2}a{t}^{2}=7¡Á6+\frac{1}{2}¡Á0.5¡Á36m$=51m£¬
¼ÓËÙÖ®ºóÊ£Óà·³ÌËùÓõÄʱ¼äΪ£º${t}_{2}=\frac{{x}_{0}-{x}_{1}}{v}=\frac{56-51}{10}s=0.5s$£®
ËùÒԳɼ¨Ìá¸ßÁË£º¡÷t=t₁-t-t₂=8-6-0.5s=1.5s£®
£¨3£©ÔÚt+t₂µÄʱ¼äÄÚ£¬ÁíÒ»ÃûÔ˶¯Ô±Ç°½øµÄ¾àÀëΪ£ºs=v₀£¨t₁+t₂£©=7¡Á£¨6+0.5£©m=45.5m£¬
Ôò¸ÃÔ˶¯Ô±±»³¬Ô½µÄ¾àÀëΪ£º¡÷s=56-5-45.5m=5.5m£®
´ð£º£¨1£©Ô˶¯Ô±¼ÓËÙ³å´ÌµÄÄ©ËÙ¶ÈΪ10m/s£»
£¨2£©Õâ¸ö³å´Ì¼ÓËÙ¹ý³Ì½«Ê¹ËûµÄ³É¼¨Ìá¸ßÁË1.5s£»
£¨3£©µ±Õâ¸öÔ˶¯Ô±µ½´ïÖÕµãʱ£¬³¬¹ýÄÇÃûÔ˶¯Ô±5.5m£®

µãÆÀ ½â¾öÎÊÌâµÄ¹Ø¼üÀíÇåÔ˶¯Ô±ÔÚÕû¸ö¹ý³ÌÖеÄÔ˶¯¹æÂÉ£¬½áºÏËÙ¶Èʱ¼ä¹«Ê½¡¢Î»ÒÆʱ¼ä¹«Ê½Áé»îÇó½â£¬ÄѶÈÖеȣ®