Question

14£®ÈçͼËùʾ£¬ÔÚÕæ¿ÕÖÐxOyƽÃæÉÏ£¬Óа뾶ΪR=1 cmµÄÔ²ÖÜ£¬A¡¢B¡¢C¡¢DΪԲÖÜÉϵÄËĸöµã£¬Èô½«µçºÉÁ¿¾ùΪq=+2.0¡Á10^-6 CµÄÁ½¸öµãµçºÉ·Ö±ð¹Ì¶¨ÔÚA¡¢BÁ½µã£®ÒÑÖª¾²µçÁ¦³£Á¿k=9.0¡Á10⁹ N•m²/C²£¬Ôò£¨¡¡¡¡£©

• A£® Á½µãµçºÉ¼äµÄ¿âÂØÁ¦´óСΪ9.0¡Á10^-3 N
• B£® CµãµÄµç³¡Ç¿¶ÈµÄ´óСΪ1.3¡Á10⁸ N/C
• C£® CµãµÄ³¡Ç¿EµÄ·½ÏòÑØyÖḺ·½Ïò
• D£® ½«Ò»ÕýµãµçºÉ´ÓCµãÒƵ½Dµã£¬µç³¡Á¦×ö¸º¹¦

Answer 1

·ÖÎö ¸ù¾Ý¿âÂض¨Âɹ«Ê½ÁÐʽ£¬¿ÉÇóÁ½µãµçºÉ¼äµÄ¿âÂØÁ¦´óС£»
ÏÈÇó½âÁ½¸öµçºÉµ¥¶À´æÔÚʱÔÚCµãµÄ³¡Ç¿£¬È»ºó¸ù¾ÝƽÐÐËıßÐζ¨ÔòºÏ³ÉµÃµ½CµãµÄ³¡Ç¿£®
¸ù¾Ýµç³¡Á¦µÄ·½ÏòÓëλÒƵķ½ÏòÅжϵ糡Á¦×öÕý¹¦»¹ÊÇ×ö¸º¹¦£®

½â´ð ½â£ºA¡¢1cm=0.01m
µçºÉÁ¿¾ùΪq=+2.0¡Á10^-6CµÄÁ½µãµçºÉ·Ö±ð¹Ì¶¨ÔÚA¡¢Bµã£¬ËüÃÇÖ®¼äµÄ¿âÂØÁ¦Îª£º
 F=k$\frac{{q}^{2}}{{£¨2R£©}^{2}}$=9.0¡Á10⁹¡Á$\frac{{£¨2.0¡Á1{0}^{-6}£©}^{2}}{{0.02}^{2}}$=90N£»¹ÊA´íÎó£»
BC¡¢Í¼ÖÐA¡¢BµãµçºÉÔÚCµã²úÉúµÄ³¡Ç¿´óСÏàµÈ£¬¾ùΪ£º
  E₁=k$\frac{q}{{L}^{2}}$=$k•\frac{q}{£¨\sqrt{2}R£©^{2}}$=9.0¡Á10⁹¡Á$\frac{2.0¡Á1{0}^{-6}}{£¨0.01\sqrt{2}£©^{2}}$N/C=9.0¡Á10⁷N/C
A¡¢BµãµçºÉÔÚCµãµÄºÏ³¡Ç¿´óСΪ£ºE=2E₁cos45¡ã=2¡Á9.0¡Á10⁷N/C¡Á$\frac{\sqrt{2}}{2}$¡Ö1.3¡Á10⁸N/C£¬³¡Ç¿·½ÏòÑØ×ÅyÖáÕý·½Ïò£»¹ÊBÕýÈ·£¬C´íÎó£»
D¡¢¸ù¾ÝµÈÁ¿Í¬ÖÖµãµçºÉµÄµç³¡Ìصã¿ÉÖª£¬ÔÚÁ½¸öµçºÉÁ¬ÏßµÄÖд¹ÏߵĶԳƵÄÁ½µãÉÏ£¬µçÊÆÊÇÏàµÈµÄ£¬¼´CµãµÄµçÊƵÈÓÚDµãµÄµçÊÆ£¬ËùÒÔ½«Ò»ÕýµãµçºÉ´ÓCµãÒƵ½Dµã£¬µç³¡Á¦²»×ö¹¦£®¹ÊD´íÎó£®
¹ÊÑ¡£ºB

µãÆÀ ±¾Ì⿼²éÁË¿âÂض¨Âɺ͵糡ǿ¶ÈµÄʸÁ¿ºÏ³ÉÎÊÌ⣬¹Ø¼üÊǸù¾ÝƽÐÐËıßÐζ¨Ôò¶Ô³¡Ç¿½øÐкϳɣ®