Question

10£®ÈçͼËùʾ£¬´«ËÍ´øÓëˮƽÃæÖ®¼äµÄ¼Ð½ÇΪ¦È=37¡ã½Ç£¬ÒÔv=2m/sµÄºã¶¨ËÙÂÊÄæʱÕëת¶¯£®Ò»¸öÖÊÁ¿Îªm=1kgµÄÎïÌåÒÔ³õËÙ¶Èv₀=10m/s´Ó´«ËÍ´øÁ½¶ËA¡¢BÖ®¼äµÄÖе㿪ʼÑØ´«ËÍ´øÏòÉÏÔ˶¯£®ÒÑÖªÎïÌåÓë´«ËÍ´øÖ®¼äµÄ¶¯Ä¦²ÁÒòÊýΪ¦Ì=0.5£¬A¡¢BÖ®¼äµÄ¾àÀëΪL=20.4m£®Ôò£º
£¨1£©ÎïÌåÑØ´«ËÍ´øÏòÉÏÔ˶¯µÄ×î´ó¾àÀëΪ¶àÉÙ£¿
£¨2£©ÎïÌåÔÚ´«ËÍ´øÉÏÔ˶¯µÄ×Üʱ¼äΪ¶àÉÙ£¿
£¨3£©ÎïÌåÔÚ´«ËÍ´øÉÏÏà¶Ô´«ËÍ´øËù×ßµÄ×Ü·³ÌΪ¶àÉÙ£¿
£¨4£©ÎïÌåÔÚ´«ËÍ´øÉÏÓÉÓÚĦ²Á¶ø²úÉúµÄÈÈÁ¿Îª¶àÉÙ£¿£¨g=10m/s²£¬sin37¡ã=0.6£¬cos37¡ã=0.8£©

Answer 1

·ÖÎö ÎïÌåÏÈÏòÉÏ×öÔȼõËÙÖ±ÏßÔ˶¯£¬ËٶȼõΪÁãºó×öÔȼÓËÙÖ±ÏßÔ˶¯£¬ËٶȺʹ«ËÍ´øÏàµÈºó£¬·ÖÎöÎïÌåµÄÊÜÁ¦Çé¿ö£¬ÔÙÅжÏÎïÌåµÄÔ˶¯Çé¿ö£¬ÓÉÅ£¶ÙµÚ¶þ¶¨Âɼ°Ô˶¯Ñ§¹æÂÉ·ÖÎö¼´¿ÉÇó½â£¬¸ù¾ÝQ=¦Ìmg¡÷xÇó½â²úÉúµÄÈÈÁ¿£®

½â´ð ½â£º£¨1£©ÎïÌå¾­¹ýʱ¼ät₁ÑØ´«ËÍ´øÏòÉÏÔ˶¯ËÙ¶ÈΪÁ㣬ÔÚʱ¼ät₁ÄÚ£¬ÎïÌåµÄλÒÆΪx₁£¬´«ËÍ´øλÒÆΪx₂£¬
¶ÔÎïÌ壬ÓУºmgsin¦È+¦Ìmgcos¦È=ma₁
v₀=a₁t₁
x₁=$\frac{1}{2}$a₁t₁²
¶Ô´«ËÍ´ø£¬ÓУºx₂=vt₁
ÒÔÉÏÁªºÏÇó½âµÃ£ºa₁=10m/s²£¬t₁=1s£¬x₁=5m£¬x₂=2m
£¨2£©ÎïÌå¾­¹ýʱ¼ät₂ÑØ´«ËÍ´øÏòÏÂÔ˶¯ËٶȺʹ«ËÍ´ø¹²ËÙ£¬ÔÚʱ¼ät₂ÄÚ£¬ÎïÌåµÄλÒÆΪx₃£¬´«ËÍ´øλÒÆΪx₄£¬´Ë¹ý³ÌÎïÌåµÄÊÜÁ¦Çé¿ö²»±ä£¬¼ÓËÙ¶ÈΪa₁²»±ä
¶ÔÎïÌ壬ÓУºv=a₁t₂
x₃=$\frac{1}{2}$a₁t₂²
¶Ô´«ËÍ´ø£¬ÓУºx₄=vt₂
ÒÔÉÏÁªºÏÇó½âµÃ£ºt₂=0.2s£¬x₃=0.2m£¬x₄=0.4m
ÎïÌå¾­¹ýʱ¼ät₃ÑØ´«ËÍ´øÏòÏÂÇ¡ºÃÀ뿪´«ËÍ´ø£¬ÉèÀ뿪ʱËÙ¶ÈΪv¡ä£¬ÔÚʱ¼ät₃ÄÚ£¬ÎïÌåµÄλÒÆΪx₅£¬´«ËÍ´øλÒÆΪx₆£¬
¶ÔÎïÌ壬ÓУºmgsin¦È-¦Ìmgcos¦È=ma₂
v¡ä=v+a₂t₃
x₅=vt₃+$\frac{1}{2}$a₂t₃²
¶Ô´«ËÍ´ø£¬ÓУºx₆=vt₃
ÓÉÌâÒâÖª£ºx₅=$\frac{L}{2}$+x₁-x₃
ÒÔÉÏÁªºÏÇó½âµÃ£ºa₂=2m/s²£¬x₅=15m£¬t₃=3s£¬x₆=6m£¬v¡ä=8m/s£¬
ÉèÎïÌåÔÚ´«ËÍ´øÉÏÔ˶¯µÄ×Üʱ¼äΪt£¬ÓУº
t=t₁+t₂+t₃
½âµÃ£ºt=4.2s
£¨3£©ÉèÎïÌåÔÚ´«ËÍ´øÉÏÏà¶Ô´«ËÍ´øÔ˶¯µÄ×Ü·³ÌΪx£¬ÓУº
x=£¨ x₁+x₂£©+£¨ x₄-x₃£©+£¨x₅-x₆£©
½âµÃ£ºx=16.2m
£¨4£©ÉèÎïÌåÔÚ´«ËÍ´øÉÏÓÉÓÚĦ²Á¶ø²úÉúµÄÈÈÁ¿ÎªQ£¬ÓУº
Q=¦Ìmgxcos¦È                      
½âµÃ£ºQ=64.8J
´ð£º£¨1£©ÎïÌåÑØ´«ËÍ´øÏòÉÏÔ˶¯µÄ×î´ó¾àÀëΪ5m£»
£¨2£©ÎïÌåÔÚ´«ËÍ´øÉÏÔ˶¯µÄ×Üʱ¼äΪ4.2s£»
£¨3£©ÎïÌåÔÚ´«ËÍ´øÉÏÏà¶Ô´«ËÍ´øËù×ßµÄ×Ü·³ÌΪ16.2m£»
£¨4£©ÎïÌåÔÚ´«ËÍ´øÉÏÓÉÓÚĦ²Á¶ø²úÉúµÄÈÈÁ¿Îª64.8J£®

µãÆÀ ±¾Ì⿼²éÅ£¶ÙµÚ¶þ¶¨ÂÉÒÔ¼°Ô˶¯Ñ§»ù±¾¹«Ê½µÄÖ±½ÓÓ¦Óã¬Òª×¢ÒâÕýÈ·ÕÆÎÕÄÜÁ¿µÄת»¯·½Ïò£¬Í¬Ê±×¢ÒâÕÆÎÕÓÉÓÚĦ²Á²úÉúµÄÄÚÄܵÈÓÚĦ²ÁÁ¦ÓëÏà¶ÔλÒƵij˻ý£¬¼´Q=¦Ìmg¡÷x£¬ÄѶÈÊÊÖУ®