Question

13£®»ñÈ¡ÄÚÄܵķ½Ê½ÓжàÖÖ£¬ÆäÖÐÓÐÒ»ÖÖ·½Ê½¾ÍÊÇͨ¹ýµçÄÜת»¯ÎªÄÚÄÜ£¬ÏÖ½«Ò»µçË®ºøÖÐÖÊÁ¿Îª2kg£¬Î¶ÈΪ20¡æµÄË®£¬¼ÓÈȵ½65¡æÐèÓÃʱ14min£¬¶øµçË®ºøÿ·ÖÖӷųöµÄÈÈÁ¿Îª3¡Á10⁴J£¬Ë®µÄ±ÈÈÈÈÝΪ4.2¡Á10³J£¨kg•¡æ£©£®
Çó£º
£¨1£©½«ÕâºøË®´Ó20¡æ¼ÓÈȵ½65¡æ£¬Ë®µÄÄÚÄÜÔö¼ÓÁ˶àÉÙ£¿
£¨2£©ÕâÖÖµçË®ºøÉÕË®µÄЧÂÊΪ¶àÉÙ£¿£¨µçË®ºøÖÐË®ÎüÊÕµÄÈÈÁ¿Õ¼µçË®ºø·Å³öÈÈÁ¿µÄ±ÈÀý£©

Answer 1

·ÖÎö £¨1£©ÖªµÀË®µÄÖÊÁ¿£¬Ë®µÄ³õκÍĩΣ¬ÀûÓù«Ê½Q=cm¡÷tÇóË®ÎüÊÕµÄÈÈÁ¿£¨ÓÐÓÃÄÜÁ¿£©£¬Ë®ÎüÊÕÈÈÁ¿ÄÚÄÜÔö¼Ó£»
£¨2£©ÀûÓù«Ê½W=PtÇóÏûºÄµÄµçÄÜ£¨×ÜÄÜÁ¿£©£¬ÀûÓù«Ê½¦Ç=$\frac{{Q}_{Îü}}{W}$¡Á100%ÇóµçË®ºøµÄЧÂÊ£®

½â´ð ½â£º£¨1£©Ë®µÄÖÊÁ¿m=2kg£¬³õÎÂt₀=20¡æ£¬ÖÕÎÂt=65¡æ£¬±ÈÈÈÈÝc=4.2¡Á10³J/£¨kg•¡æ£©£¬
Ë®ÎüÊÕµÄÈÈÁ¿£¬¼´Ë®Ôö¼ÓµÄÄÚÄÜ£º
Q_Îü=cm£¨t-t₀£©=4.2¡Á10³J/£¨kg•¡æ£©¡Á2kg¡Á£¨65¡æ-20¡æ£©=3.78¡Á10⁵J£»
£¨2£©ÏûºÄµÄµçÄÜ£º
W=14min¡Á3¡Á10⁴J/min=4.2¡Á10⁵J£¬
µçË®ºøµÄЧÂÊ£º
¦Ç=$\frac{{Q}_{Îü}}{W}$¡Á100%=$\frac{3.78¡Á1{0}^{5}J}{4.2¡Á1{0}^{5}J}$¡Á100%=90%£»
´ð£º£¨1£©Ë®µÄÄÚÄÜÔö¼ÓÁË3.78¡Á10⁵J£»£¨2£©µçË®ºøÉÕË®µÄЧÂÊΪ90%£®

µãÆÀ ±¾ÌâÊÇÒ»µÀµçѧÓëÈÈѧµÄ×ÛºÏÓ¦ÓÃÌ⣬Óëʵ¼ÊÉú»îÏàÁªÏµ£¬Ê¹Ñ§Éú¾õµÃѧÁËÎïÀíÓÐÓ㬴ÓÃúÅƱíÉϵõ½Ïà¹ØÐÅÏ¢ÊDZ¾ÌâµÄ¹Ø¼ü£®