Question

19£®ÈçͼËùʾ£¬ºá½ØÃæΪÕý·½Ðεķ½Ä¾£¬±ß³¤Îªa=0.1m£¬Ë®Æ½¹Ì¶¨£¬ÔÚÆäÉÏ·½µÄÒ»¸öÀâ½ÇOÉϹ̶¨Ò»¸ù³¤ÎªL=4aµÄÇáÉþ£¬ÇáÉþÁíÒ»¶ËË©ÒÔÖÊÁ¿Îªm=1kgµÄСÇò£¨¿ÉÊÓΪÖʵ㣩£¬µ±ÇáÉþÀ­Ö±ÇÒˮƽʱ¸øСÇòÒ»¸öÊúÖ±ÏòϵijõËÙ¶Èv₀=5m/s£¬Ê¹ÉþÒ»Ö±´¦ÓÚÀ­½ô״̬²¢²øÈÆÔÚ·½Ä¾ÉÏ£¬Ð¡Çò×îÖÕÂäÔÚOµã£¬Çó£º
£¨1£©µ±Ð¡ÇòÒ԰뾶2aͨ¹ýCµãʱ£¬ÉþµÄÀ­Á¦Îª¶à´ó£¿
£¨2£©Ð¡ÇòÔںδ¦Ê±ÉþÀ­Á¦×î´ó£¬×î´óֵΪ¶àÉÙ£¿£¨g=10m/s²£©

Answer 1

·ÖÎö ¸ù¾Ý»úеÄÜÊغ㶨ÂÉÇó³öСÇòͨ¹ýCµãµÄËٶȣ¬½áºÏÅ£¶ÙµÚ¶þ¶¨ÂÉÇó³öÀ­Á¦µÄ´óС£®
¸ù¾Ý¶¯Äܶ¨Àí·Ö±ðÇó³öB¡¢DµãµÄËٶȣ¬½áºÏÅ£¶ÙµÚ¶þ¶¨ÂÉÇó³öÀ­Á¦µÄ´óС£¬´Ó¶øÈ·¶¨ºÎ´¦À­Á¦×î´ó£®

½â´ð ½â£º£¨1£©¸ù¾Ý»úеÄÜÊغ㶨Âɵã¬
$mga=\frac{1}{2}m{v}^{2}-\frac{1}{2}m{{v}_{0}}^{2}$£¬
½âµÃCµãµÄËÙ¶Èv=$3\sqrt{3}m/s$£¬
¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨Âɵã¬F=$m\frac{{v}^{2}}{2a}$=$1¡Á\frac{27}{0.2}N=135N$£®
£¨2£©¸ù¾Ý¶¯Äܶ¨ÀíµÃ$mg•4a=\frac{1}{2}m{{v}_{B}}^{2}$-$\frac{1}{2}m{{v}_{0}}^{2}$£¬
´úÈëÊý¾Ý½âµÃ${v}_{B}=\sqrt{33}m/s$£¬
¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨Âɵã¬${F}_{B}-mg=m\frac{{{v}_{B}}^{2}}{3a}$£¬
½âµÃF_B=120N£®
¸ù¾Ý¶¯Äܶ¨ÀíµÃ£¬$-mga=\frac{1}{2}m{{v}_{D}}^{2}-\frac{1}{2}m{{v}_{0}}^{2}$£¬
´úÈëÊý¾Ý½âµÃv_D=$\sqrt{23}m/s$£¬
¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨Âɵã¬${F}_{D}+mg=m\frac{{{v}_{D}}^{2}}{a}$£¬
½âµÃF_D=220N£®
´ð£º£¨1£©ÉþµÄÀ­Á¦Îª135N£®
£¨2£©Ð¡ÇòÔÚD´¦Ê±ÉþÀ­Á¦×î´ó£¬×î´óֵΪ220N£®

µãÆÀ ±¾Ì⿼²éÁËÅ£¶ÙµÚ¶þ¶¨ÂɵĻù±¾ÔËÓ㬹ؼüÖªµÀÔ²ÖÜÔ˶¯ÏòÐÄÁ¦µÄÀ´Ô´£¬ÔËÓö¯Äܶ¨ÀíºÍÅ£¶ÙµÚ¶þ¶¨ÂÉ×ÛºÏÇó½â£®