Question

8£®ÈçͼËùʾµÄÖ±½Ç×ø±êϵÖУ¬ÔÚÖ±Ïßx=-2l₀ºÍyÖáÖ®¼äµÄÇøÓòÄÚ´æÔÚÁ½¸ö´óСÏàµÈ¡¢·½ÏòÏà·´µÄÓнçÔÈÇ¿µç³¡£¬ÆäÖÐxÖáÉÏ·½µÄµç³¡µÄ·½ÏòÑØyÖḺ·½Ïò£¬xÖáÏ·½µÄµç³¡·½ÏòÑØyÖáÕý·½Ïò£®Ôڵ糡×ó±ß½çÉÏA£¨-2L₀£¬-l₀£©µ½C£¨-2L₀£¬0£©ÇøÓòÄÚ£¬Á¬Ðø·Ö²¼×ŵçºÉÁ¿Îª+q£¬ÖÊÁ¿ÎªmµÄÁ£×Ó£®´Óijʱ¿ÌÆðÓÉAµãµ½Cµã¼äµÄÁ£×Ó£¬ÒÀ´ÎÁ¬ÐøÒÔÏàͬµÄËÙ¶ÈV₀ÑØxÖáÕý·½ÏòÉäÈëµç³¡£®Èô´ÓAµãÉäÈëµÄÁ£×Ó£¬Ç¡ºÃ´ÓyÖáÉϵÄA¡ä£¨0£¬L₀£©ÑØxÖáÕý·½ÏòÉä³öµç³¡£¬Æä¹ì¼£ÈçͼËùʾ£®²»¼ÆÁ£×ÓµÄÖØÁ¦¼°ËüÃǼäµÄÏ໥×÷Óã®Çó£º
£¨1£©ÔÈÇ¿µç³¡µÄµç³¡Ç¿¶ÈE£º
£¨2£©ÇóAC¼ä»¹ÓÐÄÄЩλÖõÄÁ£×Ó£¬Í¨¹ýµç³¡ºóÒ²ÄÜÑØxÖáÕý·½ÏòÔ˶¯£¿

Answer 1

·ÖÎö £¨1£©´ÓAµãÉä³öµÄÁ£×ÓÑØxÖá·½Ïò×öÔÈËÙÖ±ÏßÔ˶¯£¬¿ÉÇóÔ˶¯Ê±¼ä£¬ÓÉÓÚÆäÉä³öµç³¡Ê±µÄËÙ¶ÈÑسõËٶȷ½Ïò£¬²¢ÇÒÈëÉäµãÓë³öÉäµãµÄ×Ý×ø±ê¾ø¶ÔÖµÏàµÈ£¬¿ÉÖªÁ£×ÓÔÚÁ½µç³¡µÄÔ˶¯¾ßÓжԳÆÐÔ£¬ÔÚÿ¸öµç³¡ÖеÄÔ˶¯Ê±¼ä¶¼ÊÇ×Üʱ¼äµÄÒ»°ë£¬ÀûÓÃÑص糡·½ÏòµÄÔȱäËÙÔ˶¯¹æÂɿɽⳡǿ´óС
£¨2£©·²ÊÇÉä³öµç³¡ºóÄÜÑØxÖáÕý·½ÏòÔ˶¯µÄÁ£×Ó£¬Æä³öÉäʱÑØy·½ÏòµÄ·ÖËٶȱØΪÁ㣬¿ÉÖªÆäÔ˶¯¹ì¼£Ïà¶ÔÓÚxÖá¾ßÓжԳÆÐÔ£¬²¢ÇÒÔ˶¯Ê±¼äÄÚÑØxÕý·½ÏòµÄλÒƱØΪ2l₀£®

½â´ð ½â£º£¨1£©Éè´ÓAµãÉä³öµÄÁ£×ÓÔڵ糡ÖÐÔ˶¯µÄ×Üʱ¼äΪt£¬ÓÉÔ˶¯µÄ¶Ô³ÆÐÔ¿ÉÖª£º
xÖá·½Ïò£¬2l₀=v₀t£¬yÖá·½Ïò£¬l₀=$\frac{1}{2}$$\frac{qE}{m}$£¨$\frac{t}{2}$£©²£¬½âµÃ£ºE=$\frac{2m{v}_{0}^{2}}{q{l}_{0}}$£»
£¨2£©Éèµ½Cµã¾àÀëΪ¡÷y´¦µÄÁ£×Óͨ¹ýµç³¡ºóÒ²ÑØxÖáÕý·½Ïò£¬Á£×ÓµÚÒ»´Îµ½´ïxÖáÓÃʱΪ¡÷t£¬Ë®Æ½Î»ÒÆΪ¡÷x£¬Ôò
¡÷x=v₀¡÷t¡÷y=$\frac{1}{2}$$\frac{qE}{m}$£¨¡÷t£©²£¬
ÈôÂú×ã2l₀=n.2¡÷x£¬£¨n=1¡¢2¡¢3¡¢£©ÔòÁ£×Ó³öÉä·½ÏòÒ²Ò»¶¨ÑØxÖáÕý·½Ïò£¬
½âµÃ£º¡÷y=$\frac{{l}_{0}}{{n}^{2}}$£¨n=1¡¢2¡¢3¡¢£©
¼´AC¼äy×ø±êΪ£ºy=-$\frac{1}{{n}^{2}}$l₀£¨n=1¡¢2¡¢3¡¢£©
´ð£º£¨1£©ÔÈÇ¿µç³¡µÄµç³¡Ç¿¶ÈΪ$\frac{2m{v}_{0}^{2}}{q{l}_{0}}$£»
£¨2£©¼´AC¼äy×ø±êΪy=-$\frac{1}{{n}^{2}}$l₀£¨n=1¡¢2¡¢3¡¢£©µÄÁ£×Ó³öµç³¡ºóÑØxÖáÕýÏòÔ˶¯£®

µãÆÀ ±¾Ìâ¹Ø¼üÊǽ«Á£×ÓµÄÔ˶¯ÑØ×Åˮƽ·½ÏòºÍÊúÖ±·½ÏòÕý½»·Ö½â£¬È»ºó¸ù¾ÝÅ£¶ÙÔ˶¯¶¨ÂɺÍÔ˶¯Ñ§¹«Ê½ÁÐʽ·ÖÎöÇó½â£»½âÌâ¹ý³ÌÖÐÒªÇÉÃî½èÓù켣ͼ·ÖÎö£®