ÌâÄ¿ÄÚÈÝ
14£®£¨1£©ÎïÌå´Ó·ÅÉÏ´«ËÍ´ø¿ªÊ¼µ½µÚÒ»´Î»¬µ½Ë®Æ½´«ËÍ´øÓҶ˵Äʱ¼ä£»
£¨2£©ÎïÌå´Ó·ÅÉÏ´«ËÍ´ø¿ªÊ¼µ½µÚ¶þ´Î»¬µ½Ë®Æ½´«ËÍ´øÓҶ˵Äʱ¼ä£®
·ÖÎö £¨1£©ÎïÌåÔÚ´«ËÍ´øÉÏÏȼÓËÙºóÔÈËÙ£¬¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉÇóµÃ¼ÓËÙʱµÄ¼ÓËÙ¶È£¬ÔÙ½áºÏÔ˶¯Ñ§¹«Ê½ÇóµÃʱ¼ä£»
£¨2£©ÎïÌå´ïµ½Ð±ÃæºóÏÈÏòÉÏ×ö¼õËÙÔ˶¯£¬ºóÏòÏÂ×ö¼ÓËÙÔ˶¯£¬¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉÇóµÃ¼ÓËÙ¶È£¬½áºÏÔ˶¯Ñ§¹«Ê½ÇóµÃ¼´¿É
½â´ð ½â£º£¨1£©ÎïÌåÔÚ´«ËÍ´øÉϵļÓËÙ¶ÈΪa£¬¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉ¿ÉÖª¦Ìmg=ma£¬½âµÃa=¦Ìg=5m/s2
ÎïÌå´ïµ½ºÍ´«ËÍ´ø¾ßÓÐÏàͬËÙ¶ÈËùÐèʱ¼äΪt1£¬Ôò${t}_{1}=\frac{{v}_{0}}{a}=\frac{5}{5}s=1s$
ͨ¹ýµÄÎ»ÒÆ${x}_{1}=\frac{{v}_{0}}{2}{t}_{1}=2.5m$
ÔÈËÙÔ˶¯µÄʱ¼ä${t}_{2}=\frac{L-{x}_{1}}{{v}_{0}}=\frac{10-2.5}{5}s=1.5s$
ÔÚ´«ËÍ´øÉϾÀúµÄʱ¼ät=t1+t2=2.5s
£¨2£©ÔÚÐ±ÃæÉÏÏòÉÏ×ö¼õËÙÔ˶¯µÄ¼ÓËÙ¶ÈΪa¡ä£¬Ôò¦Ìmgcos¦È+mgsin¦È=ma¡ä£¬½âµÃa¡ä=10m/s2
ÏòÉϼõËÙÔ˶¯µÄʱ¼ä${t}_{3}=\frac{{v}_{0}}{a¡ä}=\frac{5}{10}s=0.5s$£¬Í¨¹ýµÄÎ»ÒÆÎª$x¡ä=\frac{{v}_{0}^{2}}{2a¡ä}=\frac{{5}^{2}}{2¡Á10}=1.25m$
¼õËÙµ½Áãºó¼ÓËÙÏ»¬£¬ÔòÏ»¬µÄ¼ÓËÙËÙΪa¡å£¬ÓÐmgsin¦È-¦Ìmgcos¦È=ma¡å£¬½âµÃa¡å=2m/s2
Ï»¬ËùÐèʱ¼ät4£¬Ôò${t}_{4}=\sqrt{\frac{2x¡ä}{a¡å}}=\sqrt{\frac{2¡Á1.25}{2}}s=\frac{\sqrt{5}}{2}s$
¾ÀíµÄʱ¼ä${t}_{×Ü}={t}_{1}+{t}_{2}+{t}_{3}+{t}_{4}=3+\frac{\sqrt{5}}{2}s$
´ð£º£¨1£©ÎïÌå´Ó·ÅÉÏ´«ËÍ´ø¿ªÊ¼µ½µÚÒ»´Î»¬µ½Ë®Æ½´«ËÍ´øÓҶ˵Äʱ¼äΪ2.5s£»
£¨2£©ÎïÌå´Ó·ÅÉÏ´«ËÍ´ø¿ªÊ¼µ½µÚ¶þ´Î»¬µ½Ë®Æ½´«ËÍ´øÓҶ˵Äʱ¼äΪ3+$\frac{\sqrt{5}}{2}s$
µãÆÀ ±¾ÌâÖ÷Òª¿¼²éÁËÅ£¶ÙµÚ¶þ¶¨ÂɺÍÔ˶¯Ñ§¹«Ê½£¬¹Ø¼üÊÇץסÔÚ´«ËÍ´øÉÏÏȼõËÙºóÔÈËÙÔ˶¯£¬Ã÷È·Ô˶¯¹ý³Ì¼´¿ÉÇóµÃ
| A£® | ÔÚ¹ú¼Êµ¥Î»£¨SIÖÆ£©ÖÐÓÐ7¸ö»ù±¾µ¥Î» | |
| B£® | ÔÚSIÖÆÖУ¬×÷Ϊ»ù±¾Á¿µÄÊdz¤¶È¡¢ÖÊÁ¿¡¢Á¦ | |
| C£® | ÔÚSIÖÆÖУ¬ÊôÓÚ»ù±¾µ¥Î»µÄÊÇm¡¢kg¡¢N | |
| D£® | NÊôÓÚSIÖÆÖеĵ¼³öµ¥Î» |
| A£® | µ±F£¼3¦Ìmgʱ£¬ÔòAÏà¶ÔµØÃæ¾²Ö¹ | |
| B£® | µ±F=$\frac{5}{2}$¦Ìmgʱ£¬ÔòAµÄ¼ÓËÙ¶ÈΪ$\frac{5}{6}$¦Ìg | |
| C£® | ÎÞÂÛFΪºÎÖµ£¬BµÄ¼ÓËٶȲ»»á³¬¹ý2¦Ìg | |
| D£® | ÎÞÂÛFΪºÎÖµ£¬AµÄ¼ÓËٶȲ»»á³¬¹ý¦Ìg |
| A£® | СÎï¿éÉÏ»¬Ê±¼ÓËÙ¶È´óС±ÈÏ»¬Ê±´ó | |
| B£® | СÎï¿éÉÏ»¬Ê±¼ä±ÈÏ»¬Ê±¼ä³¤ | |
| C£® | ¸ù¾ÝÌâÖÐÌõ¼þ¿ÉÇó³öÎï¿éÓëÐ±Ãæ¼äµÄ¶¯Ä¦²ÁÒòÊý | |
| D£® | ¸ù¾ÝÌâÖÐÌõ¼þ¿ÉÇó³öÎï¿éÑØÐ±ÃæÉÏ»¬µÄ×î´ó¾àÀë |
| A£® | $\frac{1}{2}$g | B£® | $\frac{\sqrt{3}}{2}$g | C£® | g | D£® | $\sqrt{3}$g |