Question

17£®Ð¡ÐǼҵÄÌ«ÑôÄÜÈÈË®Æ÷£¬Ë®ÏäÈÝ»ýÊÇ400L£®Ð¡ÐǽøÐÐÁËÒ»´Î¹Û²ì»î¶¯£ºÄ³ÌìÔçÉÏ£¬ËûÓÃζȼƲâµÃ×ÔÀ´Ë®µÄζÈΪ20¡æ£¬È»ºó¸øÈÈË®Æ÷Ë®ÏäËÍÂúË®£¬ÖÐÎçʱ¡°Î¶ȴ«¸ÐÆ÷¡±ÏÔʾˮÏäÖеÄË®ÎÂΪ45¡æ£®Ë®Ïä×°Âúˮʱ£¬ÇëÄãÇó½âÏÂÁÐÎÊÌ⡾c_Ë®=4.2¡Á10³ J/£¨kg•¡æ£¬ÃºÆøµÄÈÈֵΪq=4.2¡Á10⁷J/kg¡¿
£¨1£©Ë®µÄÖÊÁ¿£»
£¨2£©Ë®ÎüÊÕµÄÈÈÁ¿£»
£¨3£©Èç¹ûË®ÎüÊÕµÄÕâЩÈÈÁ¿£¬ÓÉȼÉÕúÆøÀ´Ìṩ£¬¶øúÆøÔîµÄЧÂÊΪ40%£¬ÇóÖÁÉÙÐèҪȼÉÕ¶àÉÙǧ¿ËúÆø£®

Answer 1

·ÖÎö £¨1£©ÓÉm=¦ÑV¿ÉÒÔÇó³öË®µÄÖÊÁ¿£»
£¨2£©ÀûÓÃQ_Îü=cm£¨t-t₀£©¿ÉÒÔÇó³öË®ÎüÊÕµÄÈÈÁ¿£»
£¨3£©¸ù¾ÝúÆøÔîµÄЧÂÊ£¬ÀûÓÃЧÂʹ«Ê½Çó³öúÆøÍêȫȼÉշųöµÄÈÈÁ¿£¬ÔÙÀûÓÃQ=qm¾ÍÄܼÆËã³öÐèҪúÆøµÄÖÊÁ¿£®

½â´ð ½â£º
£¨1£©Ë®µÄÌå»ý£º
V=400L=400dm³=0.4m³£¬
ÓɦÑ=$\frac{m}{V}$µÃ£ºË®µÄÖÊÁ¿£ºm=¦ÑV=1.0¡Á10³kg/m³¡Á0.4m³=400kg£»
£¨2£©Ë®ÎüÊÕµÄÈÈÁ¿£º
Q_Îü=cm£¨t-t₀£©=4.2¡Á10³J/£¨kg•¡æ£©¡Á400kg¡Á£¨45¡æ-20¡æ£©=4.2¡Á10⁷J£»
£¨3£©ÓɦÇ=$\frac{{Q}_{Îü}}{{Q}_{·Å}}$Öª£¬ÃºÆøÍêȫȼÉÕÊÍ·ÅÈÈÁ¿£º
Q_·Å=$\frac{{Q}_{Îü}}{¦Ç}$=$\frac{4.2¡Á1{0}^{7}J}{40%}$=1.05¡Á10⁸J£»
ÓÉQ_·Å=mqµÃ£º
ÐèҪúÆøµÄÖÊÁ¿m_ú=$\frac{{Q}_{·Å}}{q}$=$\frac{1.05¡Á1{0}^{8}J}{4.2¡Á1{0}^{7}J/kg}$=2.5kg£®
´ð£º£¨1£©Ë®µÄÖÊÁ¿Îª400kg£»
£¨2£©Ë®ÎüÊÕµÄÈÈÁ¿Îª4.2¡Á10⁷J£»
£¨3£©ÖÁÉÙÐèҪȼÉÕ2.5kgµÄúÆø£®

µãÆÀ ´ËÌâÊÇÒ»×ÛºÏÐ͵ÄÌâÄ¿£¬Éæ¼°µÄÁ¦Ñ§¡¢ÈÈѧ£¬°üÀ¨Ãܶȹ«Ê½µÄÓ¦Óá¢ÈÈÁ¿µÄ¼ÆËãµÈ£¬¿¼²éѧÉúµÄ×ÛºÏÓ¦ÓÃÄÜÁ¦¼°Ó¦ÓÃÎïÀí֪ʶ½â¾öʵ¼ÊÎÊÌâµÄÄÜÁ¦£¬ÌåÏÖÁËÎïÀíÓëÉú»îÏàÁªÏµµÄ˼Ï룬ÊôÓÚÄÑÌ⣮