7.1 力-2019-2020学年八年级下册初二物理【教材解读】(北师大版)

!!o $%&!!o!"-&# ãäåæç#èé$êÎsêëì#67 î:;< !! =ÃV>? !!! @�|ABC ÃDÞE FG5[GH IT�IJT# KL(("�0¥,("�0':"V"D"I"5[kÐMÛ2U!$% �0¥�0'2U!r�¹^4("�0¥,("�0'2U12À# 4c#:. "-!#Éê_}À'��ï7'% )!!* $*!"�0¡=(6lP��<!Ë�N�À'2U %*À%�0¥�0'2U!e[�0ze[À'2U &*("�0O¡�À!c(6[ö{�0¥~P��À '*("î� -Ã�8Ã!{ ("�0l� [À'2U ./!E�Äö /3[cc#"þz�º¶)|W"ÚSk=lØ =m"�$)*)¶*ÄöxÄö)|W"¶)�º¦3nÄö/) |W"�%��"&)*)�)A!wo-ÞéE�Äö"�')*# 01!% �$p$ qr o$Î$ st o$u$ vw o$x$ yz k= $l$ =m {J± ${$ Jk !!Äö$|W$Äö $!%�3a¶�º"¢|aE� Äö"®}¶Äö-~¶Äö# $"%;(-.|W)E�Äö/ )ÅÁmq"¶ac#¶-�c #¶ S# &" ¼T�R �þ¬� ¶)|W*-.)# -.|W)[c@ ¶*Äö /-[c)-.| W.#T.Ûx�a|W¶"� xÛþa|W¶)Üx�a| W¶"�xÜþa|W¶#þ Û-Ü /¦a|W¶# èé23!c#67ªí# :9 ÃDXQ'�O!l O¡XQ¥ÃbÉ '2UÀ !"�+RÃS!à °PÀlðOÀ ä�TUV:6!îàÈ �6:l 8Y *Á (("�0¥,("�0P�À'2UO!lO¡,("�0¥~P� 'À'2U �� KL ("�0¥,("�0PÀO!,("�0l�O¥~P�À'2U# lz%×!�0è�0='2U%°Ã' 4c#ªíW#:. )!*WX!"�0¡=À'2U$%°Ã'#("�0¥,("�0 PÀO!l�OO¡�@¥~'2UÀ!¦§OÀ�0èPÀ�0% °¥'#("�0�%PÀ�0!�Ol%OÀ�0# )"*�0=À'2U%�ON�"�OYZ'!e[Ú�¡*# "fg# ªí67#&'c%î67ctï67c&#ðñ ôL �ñ [á@ ~¶Äö �Ñ@ |W¶ :|W¶ -� -: |W?�: [áC |W?-. |W)E� ÄöC �Ñ�º! �Ñó�! �Ñ�� "-"#[\@�|UÃk]b�:X!}%îz?W#É#×@ï7'% )!!* $*Xo%OÀ�0!c%PÀ�0 %*@�|%PÀ�0!c%OÀ�0 &*Ãk]¥X':Àw}X¥Ãk]'À '*Ãk]¥X[(":À!abb�!ÜX¥Ãk]z[("abb? ':À ./!Äö/¶)|W*-.)":�Äöx¢:�Äö}¶Ñ"þ� Ñ~¬�|x¡)|W¶"ý!~¶Äöo}¶Äö*-x)"U�� }�*~¶Äö"þ*}¶Äö"8*}¶Äö"þ*~¶Äö"�$! %)*)o-�x8)p¶-8xo-�)¶*-.|W¶"ôL- �"�&)*)o-�x8a:�p¶"�ññ�"Äö/¶)|W* -.)"8xo-�Pa:��ññ¡)p¶"�'��# 01!' '" c#òÐt»ó )!*À(jUef#XY!Sàäx9d<!À'x9%^_!RI ^!U`,:XY# )"*c1À'Cw aC!"bc' À8ë!: !! íCdefg' À8ë!#: !! hC("!<� 'À8ë1,,: $%&'!o*+,pq!"-&# l{23!c#67ôõ :9 8Y OÀ�0 OÀµæ �� *Á UÀi j�k j�k IÀ j�k'ª� ���d¯ UÀI +V> ?!! >? IÀ+ VÀ >?'ª�� ��d¯ O¡À '�0 ª�� � � d¯ FG³ Elm wG& G& 5[À G&þlmd ë@� SG& '@� abZ BFG G& 5[À G&@�d* SG& '@� ab' (�B FG! N S G& 5[À G&@�ab ���­d O¡À '�0 @�� n�� �d¯ ��KL(�ZX� ýç!À'2Uor[ )!*Àù­d�0'ª�!Î~��ªd+ )"*À� ­d�0'@��n# ���0ÚÛ"��Ä�Êñ! ÜúÊñ!æÊñ"�n�R� �¶Ê"̄ Ä�Ê)dèQ§R �ô)��#¯R���"�� 9�)�***ÚÛ|¯¶) (Å# ¶)|W�c ��9�T{�"ãä¶��ò óÄö)45# 9O��"ãä¶��òóÄö )�}5�# (" Äö~¶)*gó� Äö~¶�µ�a45dºó �"þ�µ�a�}5�dº ó�"þ�µ*45-�}5 ��Ñdºó�#U���Ñ 3��ã-Äö~¶"45:� dºó�.û-Ä