ÌâÄ¿ÄÚÈÝ
20£®£¨1 £©Çó x1£»
£¨2£©ÇóСÆû³µ×öÔȼÓËÙÖ±ÏßÔ˶¯µÄʱ¼ä£»
£¨3£©ÈôСÆû³µÐÐÊ»¹ý³ÌÖÐËùÊÜ×èÁ¦ºãΪºãÁ¦µÄ0.3±¶£¬ÇóСÆû³µ¼ÓËÙ¹ý³ÌÖÐËùÊܵ½µÄÇ£ÒýÁ¦´óС£®
·ÖÎö £¨1£©ÓÉÍÆµ¼¹«Ê½¿ÉµÃÔȼõËÙÖ±ÏßÔ˶¯µÄÎ»ÒÆ£»
£¨2£©Ö±½ÓÓüÓËٶȵ͍ÒåʽÇó¼ÓËÙʱ¼ä£»
£¨3£©¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉÇóСÆû³µ¼ÓËÙ¹ý³ÌÖÐËùÊܵ½µÄÇ£ÒýÁ¦´óС£®
½â´ð ½â£º£¨1£©ÓÉÍÆµ¼¹«Ê½¿ÉµÃ¼õËÙÎ»ÒÆÎª£º
x1=$\frac{{v}^{2}}{2{a}_{1}}$=$\frac{1{0}^{2}}{2¡Á2}$=25m£»
£¨2£©ÓɼÓËٶȵ͍Òå¿ÉµÃ£º
t2=$\frac{¡÷v}{{a}_{2}}$=$\frac{10-0}{1}$=10s£»
£¨3£©ÓÉÅ£¶ÙµÚ¶þ¶¨ÂɿɵãºF-f=ma2£¬
¼´£ºF-0.3F=ma2
ËùÒÔÓУºF=$\frac{m{a}_{2}}{0.7}$=$\frac{2¡Á1{0}^{3}¡Á1}{0.7}$=2.86¡Á103N£®
´ð£º£¨1 £©¼õËÙÎ»ÒÆÎª25m£»
£¨2£©Ð¡Æû³µ×öÔȼÓËÙÖ±ÏßÔ˶¯µÄʱ¼äΪ10s£»
£¨3£©Ð¡Æû³µ¼ÓËÙ¹ý³ÌÖÐËùÊܵ½µÄÇ£ÒýÁ¦´óСΪ2.86¡Á103N£®
µãÆÀ ½â´ð´ËÌâµÄ¹Ø¼üÊÇÊìÁ·µØÔËÓÃÔȱäËÙÖ±ÏßÔ˶¯µÄ¹æÂɽâ´ð£®ÖªµÀÎïÌå×öÔȼõËÙÖ±ÏßÔ˶¯µ½Í£Ö¹¿ÉÒÔ·´Ïò¿´³É³õËÙ¶ÈΪ0µÄÔȼÓËÙÖ±ÏßÔ˶¯£®
Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿
10£®
ÈçͼËùʾ£¬³¤·½Ìå²£Á§Ë®²ÛÖÐÊ¢ÓÐNaClµÄË®ÈÜÒº£¬ÔÚË®²Û×ó¡¢ÓÒ²à±ÚÄÚ²à¸÷×°Ò»µ¼Ì寬£¬Ê¹ÈÜÒºÖÐͨÈëÑØxÖáÕýÏòµÄµçÁ÷I£¬ÑØyÖáÕýÏò¼Óºã¶¨µÄÔÈÇ¿´Å³¡B£®Í¼ÖÐa¡¢bÊÇ´¹Ö±ÓÚzÖá·½ÏòÉÏË®²ÛµÄǰºóÁ½ÄÚ²àÃæ£¬Ôò£¨¡¡¡¡£©
| A£® | a´¦Àë×ÓŨ¶È´óÓÚb´¦Àë×ÓŨ¶È | |
| B£® | a´¦µçÊÆ¸ßÓÚb´¦µçÊÆ | |
| C£® | ÈÜÒºµÄÉϱíÃæµçÊÆ¸ßÓÚϱíÃæµÄµçÊÆ | |
| D£® | ÈÜÒºµÄÉϱíÃæ´¦µÄÀë×ÓŨ¶È´óÓÚϱíÃæ´¦µÄÀë×ÓŨ¶È |
8£®
æÏ¶ðÎåºÅ¼Æ»®ÓÚ2017Äêµ×·¢É䣬·¢Éä³É¹¦ºóæÏ¶ðÎåºÅÔÂÇò̽²âÆ÷½«×Ô¶¯Íê³ÉÔÂÃæÑÒʯ²É¼¯ºó´ÓÔÂÇòÆð·É£®ÏÈÔÚÌù½üÔÂÇò±íÃæµÄ¹ìµÀ¢ñÉÏ·ÉÐУ¬Ö®ºó½øÈë¹ìµÀ¢ò£¬×îºóÑØ¹ìµÀ¢ó·µ»ØµØÇò£®Èç¹ûÖ»¿¼ÂÇÔÂÇòÒýÁ¦µÄÓ°Ï죬ÏÂÁÐ˵·¨ÕýÈ·µÄÊÇ£¨¡¡¡¡£©
| A£® | æÏ¶ðÎåºÅÔÚ¹ìµÀ¢òÉÏ´ÓQµãÔ˶¯µ½PµãµÄ¹ý³ÌÖÐËٶȼõС | |
| B£® | æÏ¶ðÎåºÅÔÚ¹ìµÀ¢òÉϵÄÔËÐÐÖÜÆÚ´óÓÚÔÚ¹ìµÀ¢ñÉϵÄÔËÐÐÖÜÆÚ | |
| C£® | æÏ¶ðÎåºÅÔÚ¹ìµÀ¢óÉϹýPµãʱµÄËÙ¶ÈСÓÚÆäÔÚ¹ìµÀ¢ñ¡¢¢òÉϹýPµãʱµÄËÙ¶È | |
| D£® | æÏ¶ðÎåºÅÔÚ¹ìµÀ¢óÉϹýPµãʱµÄ¼ÓËÙ¶È´óÓÚÆäÔÚ¹ìµÀ¢ñ¡¢¢òÉϹýPµãʱµÄ¼ÓËÙ¶È |
15£®
ÈçͼËùʾ£¬Îï¿éP·Å×÷ˮƽԲÅÌÉÏËæÔ²ÅÌÈÆÆäÖáÒ»Æðת¶¯£¨PÏà¶ÔÔ²Å̾²Ö¹£©Ê±£¬¹ØÓÚÎï¿éPËùÊܵÄĦ²ÁÁ¦Ff£¬ÏÂÁÐ˵·¨ÕýÈ·µÄÊÇ£¨¡¡¡¡£©
| A£® | Ħ²ÁÁ¦FfµÄ·½ÏòÒ»¶¨Ö¸ÏòÔ²ÐÄ | |
| B£® | Ô²ÅÌÔÈËÙת¶¯Ê±£¬Ä¦²ÁÁ¦Ff=0 | |
| C£® | Îï¿éµ½×ªÖáOµÄ¾àÀëÒ»¶¨µÄÇé¿öÏ£¬FfÓëÔ²ÅÌÔÈËÙת¶¯µÄ½ÇËٶȳÉÕý±È | |
| D£® | ÔÚת¶¯½ÇËÙ¶ÈÒ»¶¨µÄÇé¿öÏ£¬FfÓëÎï¿éµ½×ªÖáOµÄ¾àÀë³ÉÕý±È |
5£®
ÈçͼËùʾ£¬Ò»ÇáÖÊϸÉþÒ»¶Ë¹Ì¶¨ÓÚÊúֱǽ±ÚÉϵÄOµã£¬ÁíÒ»¶Ë¿ç¹ý¹â»¬µÄ´óС¿ÉºöÂԵ͍»¬ÂÖPÐü¹ÒÎï¿éB£¬OP¶ÎµÄÉþ×Óˮƽ£¬³¤¶ÈΪL£®ÏÖ½«Ò»´ø¹Ò¹³µÄÎï¿éA¹Òµ½OP¶ÎµÄÉþ×ÓÉÏ£¬ÒÑÖªA£¨°üÀ¨¹Ò¹³£©¡¢BµÄÖÊÁ¿¹ØÏµÎªmA=$\sqrt{3}$mB£¬µ±A¡¢BÎï¿éƽºâʱ£¬Îï¿éBÉÏÉýµÄ¸ß¶ÈΪ£¨¡¡¡¡£©
| A£® | $\frac{2}{3}$L | B£® | L | C£® | $\frac{2\sqrt{3}-3}{3}$L | D£® | 2L |
12£®
Ò»¿ÅС¸ÖÖé´ÓË®ÃæÉÏ·½Óɾ²Ö¹ÊÍ·Å£¬ÂäÈëË®ÖУ¬½¦ÆðµÄСˮÖéÌøµÃ±È¸ÖÖéÊÍ·ÅʱµÄλÖû¹¸ß£¬ÈçͼËùʾ£¬¶ÔÕâÖÖÏÖÏóÏÂÁÐ˵·¨ÖÐÕýÈ·µÄÊÇ£¨¡¡¡¡£©
| A£® | СˮÖ齦ÆðµÄ¸ß¶È³¬¹ý¸ÖÖéÏÂÂäʱµÄ¸ß¶È£¬Î¥±³ÁËÄÜÁ¿Êغ㶨ÂÉ | |
| B£® | С¸ÖÖéÏÂÂäʱ¾ßÓеÄÖØÁ¦ÊÆÄÜСÓÚ½¦ÆðµÄË®ÖéÔÚ×î¸ßµãµÄÖØÁ¦ÊÆÄÜ | |
| C£® | С¸ÖÖéÏÂÂäʱ¾ßÓеÄÖØÁ¦ÊÆÄܵÈÓÚ½¦ÆðµÄË®ÖéÔÚ×î¸ßµãµÄÖØÁ¦ÊÆÄÜ | |
| D£® | С¸ÖÖéÏÂÂäʱ¾ßÓеÄÖØÁ¦ÊÆÄÜ´óÓÚ½¦ÆðµÄË®ÖéÔÚ×î¸ßµãµÄÖØÁ¦ÊÆÄÜ |
9£®
ÈçͼËùʾ£¬Æ½ÐаåµçÈÝÆ÷³äµçºóÓëµçÔ´¶Ï¿ª£¬Õý¼«°å½ÓµØ£¬Á½°å¼äÓÐÒ»¸ö´ø¸ºµçµÄÊÔ̽µçºÉ¹Ì¶¨ÔÚPµã£®¾²µç¼ÆµÄ½ðÊôÇòÓëµçÈÝÆ÷µÄ¸º¼«°åÁ¬½Ó£¬Íâ¿Ç½ÓµØ£®ÒÔE±íʾÁ½°å¼äµÄ³¡Ç¿£¬¦Õ±íʾPµãµÄµçÊÆ£¬EP±íʾ¸ÃÊÔ̽µçºÉÔÚPµãµÄµçÊÆÄÜ£¬¦È±íʾ¾²µç¼ÆÖ¸ÕëµÄÆ«½Ç£®Èô±£³Ö¸º¼«°å²»¶¯£¬½«Õý¼«°å»ºÂýÏòÓÒÆ½ÒÆÒ»Ð¡¶Î¾àÀ루¾²µç¼Æ´øµçÁ¿¿ÉºöÂÔ²»¼Æ£©£¬¸÷ÎïÀíÁ¿±ä»¯Çé¿öÃèÊöÕýÈ·µÄÊÇ£¨¡¡¡¡£©
| A£® | EÔö´ó£¬¦Õ½µµÍ£¬EP¼õС£¬¦ÈÔö´ó | B£® | E²»±ä£¬¦Õ½µµÍ£¬EPÔö´ó£¬¦È¼õС | ||
| C£® | E²»±ä£¬¦ÕÉý¸ß£¬EP¼õС£¬¦È¼õС | D£® | E¼õС£¬¦ÕÉý¸ß£¬EP¼õС£¬¦È¼õС |