ÌâÄ¿ÄÚÈÝ
3£®Èçͼ1Ëùʾ£¬Ò»¼ÜÖ±Éý·É»úÕýÔÚ´óº£ÖеÄ×꾮ƽ̨ÉÏÖ´ÐоÈÔ®ÈÎÎñ£¬¾ÈÉúÔ±±§×ÅÊÜÔ®Õßͨ¹ýÀÂÉþ½«ÆäÌáÉýµ½·É»úÉÏ£®ÌáÉý¹ý³ÌÖзɻúÑØˮƽ·½ÏòÒÔ10m/sµÄËÙ¶ÈÔÈËÙ·ÉÀë×꾮ƽ̨£®ÒÑÖª·É»úÀë×꾮ƽ̨µÄÊúÖ±¸ß¶ÈΪ30m£»¾ÈÉúÔ±ÖÊÁ¿60kg£»ÊÜÔ®Õß40kg£»ÌáÉý¹ý³ÌÖзɻúÉϵÄÁ¦´«¸ÐÆ÷²âµÃÀÂÉþ¶Ô¾ÈÉúÔ±µÄÀÁ¦Èçͼ2Ëùʾ£¬gÈ¡10m/s2£®Ç󣺣¨1£©×î³õ2s¾ÈÉúÔ±¶ÔÊÜÔ®ÕßµÄ×÷ÓÃÁ¦£»
£¨2£©¾ÈÉúÔ±µ½´ï·É»úʱ¾à×꾮ƽ̨¶àÔ¶£®
·ÖÎö £¨1£©¶ÔÕûÌå·ÖÎö£¬¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉÇó³ö¼ÓËٶȣ¬¸ôÀë¶ÔÊÜÔ®Õß·ÖÎö£¬¸ù¾ÝÅ£¶ÙµÚ¶þ¶¨ÂÉÇó³ö¾ÈÉúÔ±¶ÔÊÜÔ®ÕßµÄ×÷ÓÃÁ¦£®
£¨2£©¸ù¾ÝλÒÆʱ¼ä¹«Ê½Çó³öÊúÖ±·½ÏòÉÏÔȼÓËÙÔ˶¯µÄλÒÆ£¬ÒÔ¼°¸ù¾ÝËÙ¶Èʱ¼ä¹«Ê½Çó³öÊúÖ±·½ÏòÉÏ2sÄ©µÄËٶȣ¬´Ó¶øµÃ³öÊúÖ±·½ÏòÉÏÔÈËÙÔ˶¯µÄʱ¼ä£¬¸ù¾ÝµÈʱÐÔÇó³öˮƽ·½ÏòÉϵÄλÒÆ£¬½áºÏƽÐÐËıßÐζ¨ÔòÇó³ö¾ÈÉúÔ±µ½´ï·É»úʱ¾à×꾮ƽ̨µÄ¾àÀ룮
½â´ð ½â£º£¨1£©ÓÉÅ£¶ÙµÚ¶þ¶¨Âɵãº
¶ÔÕûÌ壺T-£¨m1+m2£©g=£¨m1+m2£©a
¶ÔÊÜÔ®ÕߣºF-m2g=m2a
ÁªÁ¢ÒÔÉÏÁ½Ê½²¢´úÈëÊý¾ÝµÃ£ºF=600N£¬a=5m/s2
£¨2£©Ç°Á½ÃëÊúÖ±·½Ïò·¢ÉúµÄλÒÆ£º${y_1}=\frac{1}{2}at_1^2=\frac{1}{2}¡Á5¡Á{2^2}=10m$
2ÃëÄ©µÄËÙ¶ÈΪ£ºvx=at1=5¡Á2=10m/s
ÊúÖ±·½Ïò×öÔÈËÙÔ˶¯µÄʱ¼ä£º${t_2}=\frac{{y-{y_1}}}{v_x}=\frac{30-10}{10}=2s$
ˮƽ·½Ïò·¢ÉúµÄλÒÆΪ£ºx=vx£¨t1+t2£©=10¡Á£¨2+2£©=40m
¾ÈÉúÔ±¾àƽ̨µÄ¾àÀ룺$s=\sqrt{{x^2}+{y^2}}=\sqrt{{{40}^2}+{{30}^2}}=50m$£®
´ð£º£¨1£©×î³õ2s¾ÈÉúÔ±¶ÔÊÜÔ®ÕßµÄ×÷ÓÃÁ¦Îª600N£®
£¨2£©¾ÈÉúÔ±µ½´ï·É»úʱ¾à×꾮ƽ̨µÄ¾àÀëΪ50m£®
µãÆÀ ±¾Ì⿼²éÁËÅ£¶ÙµÚ¶þ¶¨ÂɺÍÔ˶¯Ñ§¹«Ê½µÄ×ÛºÏÔËÓã¬ÖªµÀÔÚÊúÖ±·½ÏòºÍˮƽ·½ÏòÉϵÄÔ˶¯¹æÂÉÊǽâ¾ö±¾ÌâµÄ¹Ø¼ü£¬ÖªµÀ¸÷·ÖÔ˶¯¾ßÓеÈʱÐÔ£®
íÀÂëÖÊÁ¿M£¨g£© | 0 | 30 | 60 | 90 | 120 | 150 |
µ¯»ÉµÄ×ÜL£¨cm£© | 6.00 | 7.15 | 8.34 | 9.48 | 10.46 | 11.79 |
£¨2£©ÓÉÉÏÒ»ÎÊËù×÷ͼÏ߿ɵýáÂÛ£ºµ¯»ÉµÄµ¯Á¦´óСºÍµ¯»ÉÉ쳤Á¿´óС³ÉÕý±È
£¨3£©¸Ãµ¯»É¾¢¶ÈϵÊýk=25N/m£¨½á¹û±£ÁôÁ½Î»ÓÐЧÊý×Ö£©£®
A£® | $\sqrt{\frac{3¦Ð}{¦ÑG}}$ | B£® | $\sqrt{\frac{¦ÑG}{3¦Ð}}$ | C£® | $\frac{1}{2}\sqrt{3¦Ð¦ÑG}$ | D£® | $2\sqrt{\frac{¦Ð¦ÑG}{3}}$ |
A£® | ¦Ñ=$\frac{3{g}_{0}}{¦ÐGd}$ | B£® | ¦Ñ=$\frac{{g}_{0}{T}^{2}}{3¦Ðd}$ | C£® | ¦Ñ=$\frac{3¦Ð}{G{T}^{2}}$ | D£® | ¦Ñ=$\frac{6M}{¦Ð{d}^{3}}$ |
A£® | v2=v1 | B£® | v2=v1£®cos¦È | C£® | v2=0 | D£® | v2=$\frac{{v}_{1}}{cos¦È}$ |