ÌâÄ¿ÄÚÈÝ
![¾«Ó¢¼Ò½ÌÍø](http://thumb.1010pic.com/pic3/upload/images/201311/139/5871f504.png)
£¨1£©¸ËabµÄËÙ¶ÈÔö´óµ½ºÎֵʱ£¬¸Ëcd¸ÕÄÜ°ÑÖØÎïÌáÆð£¿
£¨2£©Èç¹ûmÒÔ1m/sµÄËÙ¶ÈÔÈËÙÉÏÉý£¬ÄÇô¸ËabµÄËÙ¶ÈΪ¶à´ó£¿´ËʱÍâÁ¦À¶¯¸Ë×ö¹¦µÄ¹¦ÂÊÓÖΪ¶à´ó£¿
·ÖÎö£º£¨1£©ÓÉÊÜÁ¦·ÖÎöÖª¸ÕºÃ¶¯Ê±°²ÅàÁ¦µÈÓÚÎïÌåµÄÖØÁ¦£¬ÔÙÓɱպϵç·µÄÅ·Ä·¶¨Âɼ´E=BLV¿ÉÒÔ½âµÃab¸ËµÄËÙ¶Èv£»
£¨2£©ÓÉmÔÈËÙÉÏÉý¿ÉÒÔÖªmg=BI1L£¬ÔÙÓɱպϵç·µÄÅ·Ä·¶¨Âɼ´E=BLV¿ÉÒÔ½âµÃab¸ËµÄËÙ¶Èv1£»ÓÉP=FV¿ÉÒÔÇóµÃÍâÁ¦µÄ¹¦ÂÊ£®
£¨2£©ÓÉmÔÈËÙÉÏÉý¿ÉÒÔÖªmg=BI1L£¬ÔÙÓɱպϵç·µÄÅ·Ä·¶¨Âɼ´E=BLV¿ÉÒÔ½âµÃab¸ËµÄËÙ¶Èv1£»ÓÉP=FV¿ÉÒÔÇóµÃÍâÁ¦µÄ¹¦ÂÊ£®
½â´ð£º½â£º£¨1£©Éècd¸ÕºÃÄÜ°ÑÖØÎïÌáÆðʱ£¬µç·ÖеĵçÁ÷ΪI£¬´Ëʱab¸ËµÄÔ˶¯ËÙ¶ÈΪv£¬
ÔòBIL=mg ¢Ù
I=
=
¢Ú
ÁªÁ¢¢Ù¢Ú£¬´úÈëÊý¾Ý½âµÃ£ºv=
=8m/s
£¨2£©ÉèmµÄËÙ¶ÈΪv0£¬¼´v0=1m/s£¬Éè´Ëʱµç·µÄµçÁ÷ΪI1£¬¸ËabµÄËÙ¶ÈΪv1£¬
ÔòBI1L=mg ¢Û
I1=
=
¢Ü
ÁªÁ¢¢Û¢Ü´úÈëÊý¾Ý½âµÃ v=v0+
=9m/s
´ËʱÍâÁ¦µÄ¹¦ÂÊΪ P=FÍâv1=BI1Lv1=mgv1=180W
´ð£º£¨1£©¸ËabµÄËÙ¶ÈÔö´óµ½8m/sʱ£¬¸Ëcd¸ÕÄÜ°ÑÖØÎïÌáÆð£»
£¨2£©Èç¹ûmÒÔ1m/sµÄËÙ¶ÈÔÈËÙÉÏÉý£¬ÄÇô¸ËabµÄËÙ¶ÈΪ9m/s£¬´ËʱÍâÁ¦À¶¯¸Ë×ö¹¦µÄ¹¦ÂÊÓÖΪ180W£®
ÔòBIL=mg ¢Ù
I=
E |
R |
BLv |
R |
ÁªÁ¢¢Ù¢Ú£¬´úÈëÊý¾Ý½âµÃ£ºv=
mgR |
B2L2 |
£¨2£©ÉèmµÄËÙ¶ÈΪv0£¬¼´v0=1m/s£¬Éè´Ëʱµç·µÄµçÁ÷ΪI1£¬¸ËabµÄËÙ¶ÈΪv1£¬
ÔòBI1L=mg ¢Û
I1=
E1 |
R |
BL(v1-v0) |
R |
ÁªÁ¢¢Û¢Ü´úÈëÊý¾Ý½âµÃ v=v0+
mgR |
B2L2 |
´ËʱÍâÁ¦µÄ¹¦ÂÊΪ P=FÍâv1=BI1Lv1=mgv1=180W
´ð£º£¨1£©¸ËabµÄËÙ¶ÈÔö´óµ½8m/sʱ£¬¸Ëcd¸ÕÄÜ°ÑÖØÎïÌáÆð£»
£¨2£©Èç¹ûmÒÔ1m/sµÄËÙ¶ÈÔÈËÙÉÏÉý£¬ÄÇô¸ËabµÄËÙ¶ÈΪ9m/s£¬´ËʱÍâÁ¦À¶¯¸Ë×ö¹¦µÄ¹¦ÂÊÓÖΪ180W£®
µãÆÀ£º´ËÌâÒªÇóѧÉú»á¸ù¾ÝÊÜÁ¦·ÖÎöºÍµç´Å¸ÐÓ¦¶¨ÂÉÒÔ¼°Å·Ä·¶¨ÂɽâÌ⣬×ÛºÏÐÔǿЩ£®
![](http://thumb2018.1010pic.com/images/loading.gif)
Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿