£¨3£© £¨2·Ö£©
(4)+1£¨1·Ö£© sp £¨1·Ö£© ÕýËÄÃæÌ壨1·Ö£© (5)ÌåÐÄÁ¢·½ £¨1·Ö£© 2£¨1·Ö£© 74%£¨»ò
»ò
»ò
£©£¨2·Ö£©
36£®£¨15·Ö£©¡¾»¯Ñ§¡ª¡ªÑ¡ÐÞ5: Óлú»¯Ñ§»ù´¡¡¿
£¨1£©¼×±½¡¢ »ò£¨¸÷2·Ö£©£»£¨2£©È©»ù£¨2·Ö£©
£¨3£©£¨2·Ö£©
£¨4£©È¡´ú·´Ó¦¡¢ÏûÈ¥·´Ó¦£¨»òÑõ»¯·´Ó¦£©£¨¸÷1·Ö£©
£¨5£©£¨2·Ö£©
£¨6£©·Ö£©
£¨3
¡¤21¡¤
2018Ä긣ÖÝÊиßÖбÏÒµ°àÖÊÁ¿¼ì²â
Àí¿Æ×ÛºÏÊÔ¾íÎïÀí²Î¿¼´ð°¸
14£®C 15£®D 16£®C 17£®A 18£®AD 19£®AC20£®AB21£®AD 22. £¨5·Ö£©
£¨1£©B£¨2·Ö£© £¨2£©C£¨2·Ö£© £¨3£©A£¨1·Ö£© 23. £¨10·Ö£© £¨1£©F£¨2·Ö£© £¨2£©ÈçͼËùʾ£¨2·Ö£© £¨3£©2.20£¨2·Ö£©£¬4.4£¨2·Ö£© £¨4£©1.7£¨2·Ö£¬1.5¡«1.9¸ø2·Ö£© 24£®£¨14·Ö£©
½â£º(1) С»¬¿éÇ¡ºÃͨ¹ý¹ìµÀ×î¸ßµã£¬NC=0£º
2vC ÓÉÅ£¶ÙµÚ¶þ¶¨Âɵ㺠(2m£«m)g =(2m£«m) (2·Ö)
RvC£½gR (2·Ö)
(2) С»¬¿é´ÓCµã·É³ö×öƽÅ×Ô˶¯ 12
ÊúÖ±·½Ïò£º2R£½gt (1·Ö) t£½2
2
R (1·Ö) g ˮƽ·½Ïò£ºx = vCt£½2R (2·Ö)
(3) »¬¿éA¡¢BÕýÅöºóÕ³ÔÚÒ»ÆðµÄËÙ¶ÈÊÇv£¬´ÓÔ²ÐιìµÀ×îµÍµãµ½×î¸ßµã¹ý³ÌÖУ¬Óɶ¯Äܶ¨ÀíµÃ£º 122
£(2m£«m)g¡¤2R£½ (2m£«m) (vC£v) (2·Ö)
2
v£½5gR (1·Ö)
»¬¿éA¡¢BÕýÅö£¬Óɶ¯Á¿ÊغãµÃ£º2m vA= (2m£«m) v (1·Ö) ¶Ô»¬¿éA£¬Óɶ¯Á¿¶¨Àí¿ÉÖª£º
»¬¿éAÊܵ½µÄ³åÁ¿I£½¡÷p=2m vA£0 (1·Ö) = (2m£«m) v£0
¡¤22¡¤
=3m5gR (1·Ö)
25£®£¨18·Ö£©
½â£º£¨1£©É裺С»¬¿éPÓë¾øÔµ°åÒ»ÆðÏòÓÒ¼ÓËÙÔ˶¯£¬ ÓÉÅ£¶ÙµÚ¶þ¶¨Âɵ㺦Ì2 m2g=£¨m1+M£©a1(1·Ö) ½âµÃ£ºa1=2.5m/s(1·Ö) ¶ÔС»¬¿éP£¬
ÓÉÅ£¶ÙµÚ¶þ¶¨ÂÉ£ºf1= m1 a1=0.25N(1·Ö)
v0 v1 v2 v Q ¾øÔµ°å Q+¾øÔµ°å 2
f1max= ¦Ì1 m1g=0.5 N >f1 ¼ÙÉèÕýÈ·(1·Ö)
£¨2£©Ð¡»¬¿éP½øÈëµç³¡ºó£¬ É裺С»¬¿éPÏà¶Ô¾øÔµ°åÔ˶¯
P+¾øÔµ°å
0 ¶Ô¾øÔµ°å£¬ÓÉÅ£¶ÙµÚ¶þ¶¨Âɵ㺦Ì2 m2g- ¦Ì1 m1g=Ma (1·Ö) ½âµÃ£ºa = 0 £¬×öÔÈËÙÖ±ÏßÔ˶¯(1·Ö)
¶ÔС»¬¿éP£¬ÓÉÅ£¶ÙµÚ¶þ¶¨ÂÉ£ºqE - ¦Ì1 m1g=m1a1¡ä(1·Ö) ½âµÃ£ºa1¡ä=3m/s ¼ÙÉèÕýÈ·
£¨3£©É裺¸Õ½øÈëµç³¡Ê±Ð¡»¬¿éPµÄËÙ¶ÈΪv1 ÓÉÔ˶¯Ñ§¹«Ê½£ºv1?2a1l?3m/s(1·Ö)
»¬¿éP½øÈëµç³¡Ç°Ô˶¯µÄʱ¼äΪt1 = = 1.2s(1·Ö) É裺»¬¿éP»Øµ½CD±ß½çʱ¼äΪt2
12
ÓÉÔ˶¯Ñ§¹«Ê½£ºx= v1t2£ a1¡ät2= 0(1·Ö)
2½âµÃt2 = 2 s(1·Ö)
¶ÔС»¬¿éQ£¬É裺¼ÓËÙ¶È´óСΪa2 ÓÉÅ£¶ÙµÚ¶þ¶¨Âɵ㺦Ì2 m2g=m2a2a2=¦Ì2 g=1m/sÉ裺¾¹ýt3ʱ¼ä£¬Ð¡»¬¿éQÓë¾øÔµ°å¹²ËÙ ¼´£ºv1=v0-a2t3(1·Ö) ½âµÃ£ºt3?2
2
t1 P t3 t1+t2 t ·½ÏòÏò×ó(1·Ö)
v0a1
v0?v1?2.5s ¡¤23¡¤ ÓÉÅ£¶ÙµÚ¶þ¶¨Âɵ㺦Ì1 m1g=£¨m2+M£©a2¡ä ??½âµÃ£ºa25?m/s2(1·Ö) M?m26?1m1gQÏà¶ÔÓÚ¾øÔµ°åµÄ×ÜÎ»ÒÆ£º 121x1?(v0t3?a2t3)?[a1t12?v1(t3?t1)]=4.925m(1·Ö) 22С»¬¿éPÏà¶ÔÓÚ°åµÄ×ÜÎ»ÒÆ£º 1?(t1?t2?t3)2?x¡Ö5.796m(1·Ö) x2?v1(t3?t1)?v1(t1?t2?t3)?a22°åµÄ×ܳ¤¶ÈΪL=x1+ x2+l¡Ö12.52m(1·Ö) 33£®[ÎïÀí¡ª¡ªÑ¡ÐÞ3-3]£¨15·Ö£© £¨1£©ADE (5·Ö¡£Ñ¡¶Ô1¸öµÃ2·Ö£¬Ñ¡¶Ô2¸öµÃ4·Ö£¬Ñ¡¶Ô3¸öµÃ5·Ö¡£Ã¿Ñ¡´í1¸ö¿Û3·Ö£¬×îµÍµÃ·ÖΪ0·Ö£© £¨2£©£¨10·Ö£© ½â£º¢ÙÆøÌå¢òÕâÒ»¹ý³ÌΪµÈѹ±ä»¯ ³õ״̬£ºÎ¶ÈT0¡¢Ìå»ýV1=L0S £¨1·Ö£© ĩ״̬£ºÎ¶ÈT¡¢Ìå»ýV2=£¨L0+h£©S £¨1·Ö£© ¸ù¾Ý²éÀí¶¨Âɿɵãº= £¨2·Ö£© ½âµÃ£ºT£½ V1V2 T0TL0+hT0 £¨1·Ö£© L0 ¢ÚÆøÌå¢ñÕâÒ»¹ý³Ì×öµÈα仯 ³õ״̬£ºÑ¹Ç¿ p1¡ä£½p0£«£¨1·Ö£© Ìå»ýV1¡ä=L0S 2mgĩ״̬£ºÑ¹Ç¿p2¡ä£½p0£«£¨1·Ö£©Ìå»ýV2¡ä=L1¡äS mgSSÓɲ£Òâ¶ú¶¨Âɵãºp1¡äL0S£½p2¡äL1¡äS £¨2·Ö£© ½âµÃ£ºL1¡ä£½ ¡¤24¡¤ p0S+mgL0 £¨1·Ö£© p0S+2mg 34£®[ÎïÀí¡ª¡ªÑ¡ÐÞ3-4]£¨15·Ö£© £¨1£©ACE £¨5·Ö¡£Ñ¡¶Ô1¸öµÃ2·Ö£¬Ñ¡¶Ô2¸öµÃ4·Ö£¬Ñ¡¶Ô3¸öµÃ5·Ö¡£Ã¿Ñ¡´í1¸ö¿Û3·Ö£¬×îµÍµÃ·ÖΪ0·Ö£©£© £¨2£©£¨10·Ö£© ½â£º¢Ù¸ù¾ÝÌâÒâ×÷¹â·ͼ£¬¹âÏßÔÚPµã·¢ÉúÕÛÉäʱ£¬ÈëÉä½ÇΪ60¡ã£¬ÕÛÉä½ÇΪ45¡ã£¨1·Ö£© ¹Ê͸Ã÷ÎïÌåµÄÕÛÉäÂÊn£½sin 60¡ãsin 45¡ã£½6 2=1.225 £¨3·Ö£© ¢Ú Á¬½ÓPN£¬Óɼ¸ºÎ¹ØÏµ¿ÉµÃ PN¡¢PM¡¢QN¡¢QMµÄ³¤¾ùΪ2 2 a£¨1·Ö£© PN¡ÏPSN£½30¡ã£¬SN£½SP£½2 sin 15¡ã£¨1·Ö£© ¹âÔÚ͸Ã÷ÎïÌåÖеÄËÙ¶Èv£½cn£¨1·Ö£© ¹âÔÚ͸Ã÷ÎïÌåÖд«²¥ËùÓõÄʱ¼ä tPM£«QM£«QN1£½v £¨1·Ö£© ¹âÔÚ͸Ã÷ÎïÌåÍâ´«²¥ËùÓõÄʱ¼ätSP£«SN2£½ c£¨1·Ö£© ¹Ê¹â´ÓSµã·¢³öµ½É仨SµãËù¾ÀúµÄ×Üʱ¼ä t£½ta 1£«t2=5.30c »¶Ó·ÃÎÊ¡¤25¡¤ ¸ßÖÐÊÔ¾íÍø¡±¡ª¡ªhttp://sj.fjjy.org ¡°