Question

2£®ÈçͼËùʾ£¬´Ö²Úˮƽ¹ìµÀAB³¤L=2m£¬ÊúÖ±´Ö²ÚÔ²»¡¹ìµÀCD¶ÔÓ¦µÄÔ²ÐĽǦÈ=53¡ã£¬°ë¾¶R=1mÇҰ뾶ODÔÚÊúÖ±·½ÏòÉÏ£¬Ë®Æ½¹ìµÀÓëCµãµÄ¸ß¶È²îΪh=0.8m£®Ò»ÖÊÁ¿M=3kgµÄÇÒ×ã¹»³¤µÄľ°å¾²Ö¹ÔÚˮƽµØÃæÉÏ£¬Ä¾°å×ó¶Ë½ô°¤×ÅDµãÇÒľ°åÉϱíÃæ¸ÕºÃÓëDµãµÈ¸ß£®ÏÖ½«Ò»ÖÊÁ¿Îªm=2kgµÄ¿ÉÊÓΪÖʵãµÄÎï¿é£¬´Óˮƽ¹ìµÀµÄAµãÒÔ5m/sµÄ³õËÙ¶ÈÏòB»¬¶¯£¬¾­BµãºóˮƽÅ׳ö£¬Ç¡ÄÜÎÞÅöײµØ´ÓCµã½øÈëÔ²»¡¹ìµÀ²¢ÑعìµÀÏ»¬£®Îï¿éÔ˶¯µ½Dµãʱ¶Ô¹ìµÀµÄѹÁ¦Îª70N£¬Ö®ºóÎï¿é»¬Éϳ¤Ä¾°å£¬³¤Ä¾°åÓëˮƽµØÃæ¼äµÄ¶¯Ä¦²ÁÒòÊý¦Ì₁=0.1£¬Îï¿éÓ볤ľ°å¼äµÄ¶¯Ä¦²ÁÒòÊý¦Ì₂=0.4£¬¼ÆËãÖÐÈ¡g=10m/s²£¬sin53¡ã=0.8£¬cos53¡ã=0.6£®Çó£º
£¨1£©Îï¿é¾­¹ýBµãʱµÄËÙ¶È
£¨2£©Îï¿éÓëˮƽ¹ìµÀAB¼äµÄ¶¯Ä¦²ÁÒòËئÌ
£¨3£©´ÓÎï¿é»¬Éϳ¤Ä¾°åÖ®ºóµÄÔ˶¯¹ý³ÌÖУ¬Îï¿é×îÖÕ¾àDµãµÄ¾àÀ룿

Answer 1

·ÖÎö £¨1£©´ÓBµã×öƽÅ×Ô˶¯£¬ÓÉÊúÖ±·½ÏòÇóµÄµ½´ïCµãµÄÊúÖ±Ëٶȣ¬ÓÉËٶȵĺϳɼ´¿ÉÇóµÃBµãËٶȣ»
£¨2£©´ÓAµ½BÓɶ¯Äܶ¨ÀíÇóµÄĦ²ÁÒòÊý£»
£¨3£©ÀûÓÃÅ£¶ÙµÚ¶þ¶¨ÂÉÇóµÄµ½´ïDµãµÄËٶȣ¬ÇóµÄÎï¿éÔÚľ°åÉϵļÓËٶȣ¬Åжϳöľ°å¾²Ö¹£¬ÓÉÔ˶¯Ñ§¹«Ê½¼´¿ÉÇóµÃλÒÆ

½â´ð ½â£º£¨1£©ÎïÌåµ½´ïCµãÊúÖ±ËÙ¶ÈΪ${v}_{y}=\sqrt{2gh}=\sqrt{2¡Á10¡Á0.8}m/s=4m/s$
ÎïÌåÇ¡ºÃ´ÓCµã½øÈ룬¹Ê${v}_{B}=\frac{{v}_{y}}{tan¦È}=\frac{4}{\frac{4}{3}}m/s=3m/s$
£¨2£©´ÓAµ½BÓɶ¯Äܶ¨Àí¿ÉµÃ$-¦ÌmgL=\frac{1}{2}{mv}_{B}^{2}-\frac{1}{2}{mv}_{A}^{2}$
½âµÃ¦Ì=0.4
£¨3£©ÎïÌåµ½´ïDµãµÄËÙ¶ÈÓÉÅ£¶ÙµÚ¶þ¶¨ÂɿɵÃ$N-mg=\frac{{mv}_{D}^{2}}{R}$
½âµÃv_D=5m/s
ľ¿éµÄ¼ÓËÙ¶ÈΪ${a}_{1}=\frac{{¦Ì}_{2}mg}{m}=2m/{s}^{2}$
ľ°åÊܵ½µÄĦ²ÁÁ¦Îª¦Ì₁£¨M+m£©g=5N£¾¦Ì₂mg=4N£¬¹Êľ°å¾²Ö¹£¬
ľ¿éÇ°½øµÄλÒÆΪ$x=\frac{{v}_{D}^{2}}{2{a}_{1}}=\frac{25}{2¡Á2}m=6.25m$
´ð£º£¨1£©Îï¿é¾­¹ýBµãʱµÄËÙ¶ÈΪ3m/s
£¨2£©Îï¿éÓëˮƽ¹ìµÀAB¼äµÄ¶¯Ä¦²ÁÒòËئÌΪ0.4
£¨3£©´ÓÎï¿é»¬Éϳ¤Ä¾°åÖ®ºóµÄÔ˶¯¹ý³ÌÖУ¬Îï¿é×îÖÕ¾àDµãµÄ¾àÀë6.25m

µãÆÀ ±¾ÌâÇ°Á½ÎÊÊÇÒ»¸öµ¥ÎïÌå¶à¹ý³ÌµÄÁ¦Ñ§ÎÊÌ⣬°Ñ¸´ÔӵĹý³Ì·Ö½â³É¼¸¸ö·Ö¹ý³ÌÊÇ»ù±¾Ë¼Â·£»µÚÈýÎÊÊÇÒ»¸ö¶à¹ý³ÌÎÊÌ⣬Ҫ·ÖÎöÇå³þÁ½¸öÎïÌåµÄÔ˶¯Çé¿ö£¬È»ºó¸ù¾ÝÔ˶¯Ñ§¹«Ê½ÁÐʽÇó½â