Question

6£®Ì«ÑôÄÜÈÈË®Æ÷ÊÇ°ÑÌ«ÑôÄÜת»¯ÎªÄÚÄܵÄÉ豸£¬ÈÈË®Æ÷ÿСʱƽ¾ù½ÓÊÕ4.2¡Á10⁶JµÄÌ«ÑôÄÜ£¬ÈÈË®Æ÷µÄЧÂÊΪ40%£¬ÔÚ5СʱµÄÓÐЧÕÕÉäʱ¼äÄÚ£¬Çó£º
£¨1£©¸ÃÈÈË®Æ÷Äܽ«ÖÊÁ¿Îª100kg¡¢³õÎÂΪ20¡æµÄˮζÈÉý¸ßµ½¶àÉ١棿[Ë®µÄ±ÈÈÈÈÝC=4.2¡Á10³J/£¨kg£®¡æ£©]
£¨2£©Èô¸ÄÓÃúÆøÀ´¼ÓÈÈÕâЩˮ£¬ÐèÒªÍêȫȼÉÕ¶àÉÙǧ¿ËúÆø£¿£¨ÃºÆøµÄÈÈÖµq=4.2¡Á10⁷J/kg£¬¼ÙÉèúÆøȼÉշųöµÄÈÈÁ¿50%±»Ë®ÎüÊÕ£©

Answer 1

·ÖÎö £¨1£©Ì«ÑôÄÜÈÈË®Æ÷ÿСʱƽ¾ù½ÓÊÜ4.2¡Á10⁶JµÄÌ«ÑôÄÜ£¬Çó³öÔÚ5СʱµÄÓÐЧÕÕÉäʱ¼äÄÚÈÈË®Æ÷½ÓÊÕµ½µÄÌ«ÑôÄÜ£»¸ù¾ÝÈÈË®Æ÷µÄЧÂÊ£¬¼ÆËã³öË®ÎüÊÕµÄÈÈÁ¿£¬ÀûÓÃQ=cm£¨t-t₀£©Çó³öË®µÄÖÕΣ»
£¨2£©ÃºÆø·Å³öµÄÈÈÁ¿µÈÓÚË®ÎüÊÕµÄÈÈÁ¿£¬¸ù¾ÝQ=mqÇó³öÍêȫȼÉÕúÆøµÄÖÊÁ¿£®

½â´ð ½â£º£¨1£©ÈÈË®Æ÷ÔÚ5СʱÄÚ½ÓÊÕµÄÌ«ÑôÄÜ E=4.2¡Á10⁶J¡Á5=2.1¡Á10⁷J£¬
ÓɦÇ=$\frac{{Q}_{Îü}}{{Q}_{·Å}}$µÃË®ÎüÊÕµÄÈÈÁ¿£º
Q_Îü=E¦Ç=2.1¡Á10⁷J¡Á40%=8.4¡Á10⁶J£¬
ÓÉQ_Îü=cm£¨t-t₀£©µÃ£¬Ë®Éý¸ßζȣº
¡÷t=$\frac{{Q}_{Îü}}{c{m}_{Ë®}}$=$\frac{8.4¡Á1{0}^{6}J}{4.2¡Á1{0}^{3}J/£¨kg•¡æ£©¡Á100kg}$=20¡æ£¬
Ë®µÄÖÕΣºt=t₀+¡÷t=20¡æ+20¡æ=40¡æ£»
£¨2£©ÓɦÇ=$\frac{{Q}_{Îü}}{{Q}_{·Å}}$µÃúÆøÐè·Å³öÈÈÁ¿£º
Q_·Å=¦ÇQ_·Å=$\frac{{Q}_{Îü}}{¦Ç}$=$\frac{8.4¡Á1{0}^{6}J}{50%}$=1.68¡Á10⁷J£»
ÓÉQ_·Å=mqµÃ£¬ÐèҪúÆøµÄÖÊÁ¿£º
m_úÆø=$\frac{{Q}_{·Å}}{q}$=$\frac{1.68¡Á1{0}^{7}J}{4.2¡Á1{0}^{7}J/kg}$=0.4kg£®
´ð£º£¨1£©ÈÈË®Æ÷Äܽ«ÖÊÁ¿Îª100kg¡¢³õÎÂΪ20¡æµÄˮζÈÉý¸ßµ½40¡æ£»
£¨2£©ÐèÒªÍêȫȼÉÕ0.4ǧ¿ËúÆø£®

µãÆÀ ´ËÌâÖ÷Òª¿¼²éµÄÊÇѧÉú¶ÔÈÈÁ¿¼ÆË㹫ʽ¡¢ÈÈÖµ¼ÆË㹫ʽ¡¢Ð§ÂʼÆË㹫ʽµÄÀí½âºÍÕÆÎÕ£¬×ÛºÏÐÔ½ÏÇ¿£®