Question

£¨8·Ö£©ÌøÉ¡Ô˶¯Ô±×öµÍ¿ÕÌøÉ¡±íÑÝ£¬ËûÔÚÀëµØÃæ224 m¸ß´¦£¬Óɾ²Ö¹¿ªÊ¼ÔÚÊúÖ±·½Ïò

×ö×ÔÓÉÂäÌåÔ˶¯£®Ò»¶Îʱ¼äºó£¬Á¢¼´´ò¿ª½µÂäÉ¡£¬ÒÔ12£®5 m/s²µÄ¼ÓËÙ¶ÈÔȼõËÙϽµ£¬ÎªÁËÔ˶¯Ô±µÄ°²È«£¬ÒªÇóÔ˶¯Ô±ÂäµØËÙ¶È×î´ó²»µÃ³¬¹ý5 m/s£¨gÈ¡10 m/s²£©£®

       £¨1£©ÇóÔ˶¯Ô±Õ¹¿ªÉ¡Ê±£¬ÀëµØÃæ¸ß¶ÈÖÁÉÙΪ¶àÉÙ?×ŵØʱÏ൱ÓÚ´Ó¶à¸ß´¦×ÔÓÉÂäÏÂ?

       £¨2£©ÇóÔ˶¯Ô±ÔÚ¿ÕÖеÄ×î¶Ìʱ¼äÊǶàÉÙ?

Answer 1

£¨1£©ÉèÔ˶¯Ô±×ö×ÔÓÉÂäÌåÔ˶¯µÄ¸ß¶ÈΪhʱËÙ¶ÈΪv£¬´Ëʱ´ò¿ªÉ¡¿ªÊ¼ÔȼõËÙÔ˶¯£¬Âä

µØʱËٶȸպÃΪ5 m/s£¬ÕâÖÖÇé¿öÔ˶¯Ô±ÔÚ¿ÕÖÐÔ˶¯Ê±¼ä×î¶Ì£¬ÔòÓÐ

v²£½2gh                                                                                                                                       £¨1·Ö£©

v_t²£­v²£½2a£¨H£­h£©                                                                                                                  

ÓÉ¢Ù¢ÚÁ½Ê½½âµÃh£½125 £í£¬v£½50 £í£¯s                                  £¨1·Ö£©

Ϊ°²È«×ŵأ¬Õ¹¿ªÉ¡Ê±µÄ¸ß¶ÈÖÁÉÙΪH£­h£½224 £í£­125 £í£½99 £í£®       £¨1·Ö£©

ËûÒÔ5 m/sµÄËÙ¶È×ŵØʱ£¬Ï൱ÓÚ´Óh¡ä¸ß´¦×ÔÓÉÂäÏ£¬ÓÉv_t²£½2gh¡ä

µÃh¡ä£½ £í£½1£®25 £í                                       £¨1·Ö£©

£¨2£©ËûÔÚ¿ÕÖÐ×ÔÓÉÏÂÂäµÄʱ¼äΪt₁£½ s£½5 s               £¨1·Ö£©

Ëû¼õËÙÔ˶¯µÄʱ¼äΪt₂£½ £í£¯s£½3£®6 s          £¨1·Ö£©

ËûÔÚ¿ÕÖеÄ×î¶Ìʱ¼äΪt£½t₁£«t₂£½8£®6 s                                   £¨2·Ö£©