Question

13£®ÖÊÁ¿Îªm=2¡Á10³kgµÄÆû³µ·¢¶¯»ú¶î¶¨¹¦ÂÊP=80kW£®Æû³µÔÚƽֱµÄ·ÃæÉÏÔ˶¯Ê±Êܵ½µÄ×èÁ¦ÎªÆäÖØÁ¦µÄ0.1±¶£®È¡g=10m/s²£¬Çó
£¨1£©Æû³µÒԶ¹¦ÂÊÔÚƽֱ·µÄÃæÉÏÐÐÊ»ÄÜ´ïµ½µÄ×î´óËÙ¶Èv_m£»
£¨ 2 £© ÈôÆû³µÓɾ²Ö¹¿ªÊ¼±£³Ö¹¦ÂÊP=60kWÆô¶¯£¬Æû³µËÙ¶ÈΪ10m/sʱµÄ¼ÓËٶȴóС£»
£¨3£©ÈôÆû³µÓɾ²Ö¹¿ªÊ¼ÒÔa=1m/s²µÄ¼ÓËÙ¶ÈÔȼÓËÙÆô¶¯£¬ÇóÆû³µÔȼÓËÙÔ˶¯ÄÜ´ïµ½µÄ×î´óλÒÆ£®

Answer 1

·ÖÎö £¨1£©µ±Æû³µµÄÇ£ÒýÁ¦µÈÓÚ×èÁ¦Ê±£¬Æû³µµÄËÙ¶È×î´ó£¬¸ù¾ÝP=fv_mÇó³öÆû³µÔÚƽֱ·ÃæÉÏÐÐÊ»´ïµ½µÄ×î´óËٶȣ®
£¨2£©¸ù¾ÝP=FvÇó³öÇ£ÒýÁ¦µÄ´óС£¬½áºÏÅ£¶ÙµÚ¶þ¶¨ÂÉÇó³öÆû³µµÄ¼ÓËٶȣ®
£¨3£©¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉÇó³öÇ£ÒýÁ¦µÄ´óС£¬½áºÏP=FvÇó³öÔȼÓËÙÖ±ÏßÔ˶¯µÄÄ©Ëٶȣ¬¸ù¾ÝËÙ¶ÈλÒƹ«Ê½Çó³öÔȼÓËÙÖ±ÏßÔ˶¯µÄλÒÆ£®

½â´ð ½â£º£¨1£©µ±Ç£ÒýÁ¦µÈÓÚ×èÁ¦Ê±£¬ËÙ¶È×î´ó£¬¸ù¾ÝP=fv_mµÃ£¬
×î´óËÙ¶È${v}_{m}=\frac{P}{f}=\frac{80000}{0.1¡Á2¡Á1{0}^{4}}m/s=40m/s$£®
£¨2£©¸ù¾ÝP=FvµÃ£¬Æû³µµÄÇ£ÒýÁ¦F=$\frac{P}{v}=\frac{60000}{10}N=6000N$£¬
¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨Âɵã¬Æû³µµÄ¼ÓËÙ¶Èa=$\frac{F-f}{m}=\frac{6000-2000}{2000}m/{s}^{2}=2m/{s}^{2}$£®
£¨3£©¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨Âɵã¬F-f=ma£¬½âµÃÇ£ÒýÁ¦F=ma+f=2000¡Á1+2000N=4000N£¬
ÔòÔȼÓËÙÖ±ÏßÔ˶¯µÄÄ©ËÙ¶Èv¡ä=$\frac{P}{F}=\frac{80000}{4000}m/s=20m/s$£¬
ÔȼÓËÙÖ±ÏßÔ˶¯µÄλÒÆx=$\frac{v{¡ä}^{2}}{2a}=\frac{400}{2¡Á1}m=200m$£®
´ð£º£¨1£©Æû³µÒԶ¹¦ÂÊÔÚƽֱ·µÄÃæÉÏÐÐÊ»ÄÜ´ïµ½µÄ×î´óËÙ¶ÈΪ40m/s£»
£¨2£©Æû³µËÙ¶ÈΪ10m/sʱµÄ¼ÓËٶȴóСΪ2m/s²£»
£¨3£©Æû³µÔȼÓËÙÔ˶¯ÄÜ´ïµ½µÄ×î´óλÒÆΪ200m£®

µãÆÀ ±¾Ì⿼²éÁË»ú³µµÄÆô¶¯ÎÊÌ⣬ÀíÇå»ú³µÆô¶¯ÔÚÕû¸ö¹ý³ÌÖеÄÔ˶¯¹æÂÉÊǽâ¾ö±¾ÌâµÄ¹Ø¼ü£¬ÖªµÀ·¢¶¯»ú¹¦ÂÊÓëÇ£ÒýÁ¦¡¢ËٶȵĹØϵ£¬ÖªµÀ¼ÓËÙ¶ÈΪÁãʱ£¬ËÙ¶È×î´ó£®