Question

17£®ÈçͼËùʾµÄºÚÏ»×Óµ×Ãæ»ýΪS=1.5¡Á10^-2 m²¡¢ÖÊÁ¿Îªm=30kg£®ºÚÏ»×ÓÔÚº£Ë®ÖУ¬¿ÉÒÔ·¢ËÍÈ˶úÌý²»µ½µÄ³¬Éù²¨Âö³å£¬ºÚÏ»×Ó·¢³öµÄÂö³å´ÓÉîΪh=3850mµÄº£µ×´¹Ö±´«µÝµ½º£Ãæ¿ÉÒÔ±»ËѾȴ¬½ÓÊÕ£®£¨g=10N/kg£¬º£Ë®µÄ¦Ñ=1.1¡Á10³kg/m³£©ÎÊ£º
£¨1£©´òÀ̹ý³ÌÖУ¬ºÚÏ»×ÓÖð½¥ÉÏÉý£¨Î´Â¶³öË®Ã棩£¬ËüÊܵ½¸¡Á¦´óСÈçºÎ±ä»¯£¿
²»±ä£¨Ìî¡°±ä´ó¡±¡¢¡°±äС¡±»ò¡°²»±ä¡±£©
£¨2£©ÔÚº£Ë®ÖÐÊܵ½µÄ¸¡Á¦Îª99N£¬´ËºÚÏ»×ÓµÄÌå»ý¶à´ó£¿
£¨3£©ºÚÏ»×ÓµÄÖØÁ¦£¿
£¨4£©Æ½·ÅÔÚˮƽµØÃæʱ£¬µØÃæÊܵ½µÄѹǿÊǶà´ó£¿
£¨5£©ºÚÏ»×Ó·¢ÉäµÄ³¬Éù²¨µ½´ïËѾȴ¬Òª¶àÉÙʱ¼ä£¿£¨³¬Éù²¨ÔÚº£Ë®ÖеÄËÙ¶ÈÊÇ1540m/s£©

Answer 1

·ÖÎö £¨1£©¸¡Á¦´óСÓëÎïÌåÅÅ¿ªÒºÌåµÄÌå»ýºÍÒºÌåÃܶÈÓйأ»
£¨2£©ºÚÏ»×ÓÈ«²¿½þûÔÚË®ÖУ¬ÅÅ¿ªË®µÄÌå»ý¼´ÎªºÚÏ»×ÓµÄÌå»ý£¬¸ù¾Ý¸¡Á¦¹«Ê½±äÐοÉÇóµÃºÚÏ»×ÓµÄÌå»ý£»
£¨3£©¸ù¾ÝºÚÏ»×ÓµÄÖÊÁ¿¿ÉÇóµÃÆäÖØÁ¦£»
£¨4£©ºÚÏ»×Ó¶ÔµØÃæµÄѹÁ¦µÈÓÚºÚÏ»×ÓµÄÖØÁ¦£¬ÀûÓÃp=$\frac{F}{S}$ÇóµÃµØÃæÊܵ½µÄѹǿ£»
£¨5£©ÓÉËٶȹ«Ê½±äÐοÉÇóµÃºÚÏ»×Ó·¢ÉäµÄ³¬Éù²¨µ½´ïËѾȴ¬Òª¶àÉÙʱ¼ä£®

½â´ð ½â£º£¨1£©´òÀ̹ý³ÌÖУ¬ºÚÏ»×Ó䶳öË®Ãæ֮ǰ£¬ÅÅ¿ªº£Ë®µÄÌå»ý²»±ä£¬¸ù¾ÝF_¸¡=¦Ñ_ÒºgV_ÅÅ¿ÉÖªËüÊܵ½¸¡Á¦´óС²»±ä£»
£¨2£©ÒòΪ½þûÔÚº£Ë®ÖУ¬ÓÉF_¸¡=¦Ñ_ÒºgV_Åŵãº
ºÚÏ»×ÓµÄÌå»ý£º
V=V_ÅÅ=$\frac{{F}_{¸¡}}{{¦Ñ}_{º£Ë®}g}$=$\frac{99N}{1.1¡Á{10}^{3}kg/{m}^{3}¡Á10N/kg}$=9¡Á10^-3m³£»
£¨3£©ºÚÏ»×ÓµÄÖØÁ¦£º
G=mg=30kg¡Á10N/kg=300N£»
£¨4£©Æ½·ÅÔÚˮƽµØÃæʱ£¬ºÚÏ»×Ó¶ÔµØÃæµÄѹÁ¦µÈÓÚºÚÏ»×ÓµÄÖØÁ¦£¬¼´F=G£¬
ºÚÏ»×Ó¶ÔµØÃæµÄѹǿÊÇ£º
p=$\frac{F}{S}$=$\frac{300N}{1.5¡Á{10}^{-2}{m}^{2}}$=2¡Á10⁴Pa£»
£¨5£©ÓÉv=$\frac{s}{t}$µÃ£¬
ºÚÏ»×Ó·¢ÉäµÄ³¬Éù²¨µ½´ïËѾȴ¬ÐèÒªµÄʱ¼ä£º
t=$\frac{s}{v}$=$\frac{3850m}{1540m/s}$=2.5s£®    
´ð£º£¨1£©²»±ä£»
£¨2£©ÔÚº£Ë®ÖÐÊܵ½µÄ¸¡Á¦Îª99N£¬´ËºÚÏ»×ÓµÄÌå»ýΪ9¡Á10^-3m³£»
£¨3£©ºÚÏ»×ÓµÄÖØÁ¦Îª300N£»
£¨4£©Æ½·ÅÔÚˮƽµØÃæʱ£¬µØÃæÊܵ½µÄѹǿÊÇ2¡Á10⁴Pa£»
£¨5£©ºÚÏ»×Ó·¢ÉäµÄ³¬Éù²¨µ½´ïËѾȴ¬Òª2.5s£®

µãÆÀ ´ËÌâͨ¹ý´òÀ̺ÚÏ»×ÓÕâһʼþ£¬¿¼²éÖØÁ¦µÄ¼ÆË㣬ѹǿµÄ¼ÆË㣬Ëٶȹ«Ê½µÄÓ¦Ó㬸¡Á¦µÄ¼ÆËãµÈ¶à¸ö֪ʶµã£¬ÊÇÒ»µÀ×ÛºÏÐÔ½ÏÇ¿µÄÌâÄ¿£®