ÌâÄ¿ÄÚÈÝ

14£®ÈçͼËùʾ£¬Ë®Æ½´«ËÍ´øµÄÓҶ˹̶¨Ò»¸ö×ã¹»³¤µÄÐ±Ãæ£¬Ð±ÃæÓëË®Æ½ÃæµÄ¼Ð½ÇΪ¦È=37¡ã£¬³¤Îªl=10mµÄ´«ËÍ´øÒÔv=5m/sµÄËÙ¶È˳ʱÕë´«¶¯£¬ÔÚˮƽ´«ËÍ´øµÄ×ó¶ËÎÞ³õËٶȵÄÇá·ÅÒ»¸öÖÊÁ¿ÎªmÎïÌ壬ˮƽ´«ËÍ´øºÍÐ±ÃæÓëÎïÌå¼äµÄ¶¯Ä¦²ÁÒòÊý¾ùΪ¦Ì=0.5£¬ÎïÌå´Ó´«ËÍ´ø»¬ÉÏÐ±ÃæÊ±ËٶȵĴóС±£³Ö²»±ä£®Çó£º
£¨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

Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿

Î¥·¨ºÍ²»Á¼ÐÅÏ¢¾Ù±¨µç»°£º027-86699610 ¾Ù±¨ÓÊÏ䣺58377363@163.com

¾«Ó¢¼Ò½ÌÍø