ÌâÄ¿ÄÚÈÝ
15£®ÈçͼËùʾ£¬³¤L=1.6m£¬ÖÊÁ¿M=3kgµÄľ°å¾²·ÅÔڹ⻬ˮƽÃæÉÏ£¬ÖÊÁ¿m=1kgµÄСÎï¿é·ÅÔÚľ°åµÄÓҶˣ¬Ä¾°åºÍСÎï¿é¼äµÄ¶¯Ä¦²ÁÒòÊý¦Ì=0.1£®ÏÖ¶Ôľ°åÊ©¼ÓһˮƽÏòÓÒµÄÀÁ¦F£¬È¡g=10m/s2£®£¨1£©ÇóʹСÎï¿é²»µôÏÂÈ¥µÄ×î´óÀÁ¦F£»
£¨2£©Èç¹ûÀÁ¦F=10Nºã¶¨²»±ä£¬·Ö±ðÇó³öСÎï¿éºÍľ°åµÄ¼ÓËٶȣ»
£¨3£©ÊÔ¼ÆËãµ±ÀÁ¦F=10Nºã¶¨²»±äʱ£¬Ð¡Îï¿éËùÄÜ»ñµÃµÄ×î´óËÙ¶Èvm£®
·ÖÎö £¨1£©ÇóÎï¿é²»µôÏÂʱµÄ×î´óÀÁ¦£¬Æä´æÔÚµÄÁÙ½çÌõ¼þ±ØÊÇÎï¿éÓëľ°å¾ßÓй²Í¬µÄ×î´ó¼ÓËٶȣ¬ÏÈÒÔСÎïÌåΪÑо¿¶ÔÏó£¬ÓÉÅ£¶ÙµÚ¶þ¶¨ÂÉÇó³ö¼ÓËٶȣ¬ÔÙÒÔÕûÌåΪÑо¿¶ÔÏóÇó½âFµÄ×î´óÖµ£®
£¨2£©ÓÉÌâF=10Nʱ£¬Ð¡ÎïÌåÏà¶ÔÓÚľ°åÏà¶Ô»¬¶¯£¬¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉ·Ö±ðÇó³öСÎïÌåºÍľ°åµÄ¼ÓËٶȣ®
£¨3£©µ±Ð¡ÎïÌåÀ뿪ľ°åʱ£¬Ä¾°åÏà¶ÔÓÚСÎïÌåµÄλÒƵÈÓÚL£¬ÓÉλÒƹ«Ê½Çó³öʱ¼ä£¬ÔÙÓÉËٶȹ«Ê½Çó½âСÎïÌåÀ뿪ľ°åʱµÄËٶȣ®
½â´ð ½â£º£¨1£©ÇóСÎï¿é²»µôÏÂʱµÄ×î´óÀÁ¦£¬Æä´æÔÚµÄÁÙ½çÌõ¼þ±ØÊÇСÎï¿éÓëľ°å¾ßÓй²Í¬µÄ×î´ó¼ÓËÙ¶Èa1
¶ÔСÎï¿é£¬¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉÓÐ×î´ó¼ÓËÙ¶È
a1=$\frac{¦Ìmg}{m}$=¦Ìg=0.1¡Á10=1 m/s2
¶ÔÕûÌ壬ÓÉÅ£¶ÙµÚ¶þ¶¨ÂɵÃF=£¨M+m£©a1=£¨3+1£©¡Á1 N=4 N
£¨2£©ÓÉÓÚF=10 N£¾4 N£¬Ð¡Îï¿é½«Ïà¶ÔÓÚľ°åÏò×óÔ˶¯£¬ËùÒÔľ°å¶ÔСÎï¿éµÄĦ²ÁÁ¦ÏòÓÒ£¬¶øСÎï¿é¶Ôľ°åµÄĦ²ÁÁ¦Ïò×ó£®
СÎï¿éµÄ¼ÓËÙ¶Èa1=¦Ìg=1 m/s2
ľ°åµÄ¼ÓËÙ¶Èa2=$\frac{F-¦Ìmg}{m}$=$\frac{10-0.1¡Á10}{3}$ m/s2=3 m/s2
£¨3£©ÓÉÓÚСÎï¿éÒ»Ö±×ö¼ÓËÙÔ˶¯£¬ËùÒÔµ±Ð¡Îï¿é¸ÕÀ뿪ľ°åʱËÙ¶È×î´ó
СÎï¿é¸ÕÀ뿪ľ°åÇ°£¬ÓÉ$\frac{1}{2}$a2t2-$\frac{1}{2}$a1t2=L£¬
½âµÃСÎï¿é»¬¹ýľ°åËùÓÃʱ¼ät=$\sqrt{1.6}$ s
СÎï¿éÀ뿪ľ°åµÄËÙ¶Èv1=a1t=1¡Á$\sqrt{1.6}$=$\sqrt{1.6}$ m/s£¬
ËùÒÔСÎï¿éËùÄÜ»ñµÃµÄ×î´óËÙ¶ÈΪ$\sqrt{1.6}$m/s
´ð£º£¨1£©Ê¹Ð¡Îï¿é²»µôÏÂÈ¥µÄ×î´óÀÁ¦FΪ4 N £¨2£©Ð¡Îï¿éÒÔ1 m/s2µÄ¼ÓËÙ¶ÈÏòÓÒ×öÔȼÓËÙÔ˶¯£¬Ä¾°åÒÔ3 m/s2µÄ¼ÓËÙ¶ÈÏòÓÒ×öÔȼÓËÙÔ˶¯ £¨3£©Ð¡Îï¿éËùÄÜ»ñµÃµÄ×î´óËÙ¶ÈΪ$\sqrt{1.6}$m/s
µãÆÀ ±¾ÌâÖÐÉæ¼°ÁÙ½çÎÊÌ⣺µ±Á½½Ó´¥ÎïÌå¸ÕÒªÏà¶Ô»¬¶¯Ê±£¬¾²Ä¦²ÁÁ¦´ïµ½×î´ó£¬Í¬Ê±×¢Òâ·ÖÎö¹ý³Ì£¬ÌرðÊǵÚÈýÎÊÖÐÒªÈÏÕæ·ÖÎöÁ½ÎïÌåµÄÔ˶¯¹ý³Ì£¬Ã÷ȷλÒƹØϵÊǽâÌâµÄ¹Ø¼ü£®
A£® | Ô˶¯Ê±¼ä0.3s | B£® | Ô˶¯Ê±¼ä0.4s | ||
C£® | ƽ¾ùËٶȴóСÊÇ0.17m/s | D£® | ƽ¾ùËÙ¶ÈÊÇ0.2m/s |
A£® | Á£×Óa´øÕýµç£¬Á£×Ób´ø¸ºµç | |
B£® | Á£×Óa¡¢bÔڴų¡ÖÐÔ˶¯µÄ¼ÓËٶȴóС֮±ÈΪ5£º2 | |
C£® | Á£×Óa¡¢bµÄËÙÂÊÖ®±ÈΪ2£º5 | |
D£® | Á£×Óa¡¢bÔڴų¡ÖÐÔ˶¯µÄʱ¼äÖ®±ÈΪ180£º53 |