Question

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Answer 1

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½âµÃ v1 =  m/s    ÉèµÚ¶þ´ÎÉÏÉýʱ³õËÙ¶ÈΪ v2 £¬ 
Ôò £¨mg + f £©h2 =m v22 ½âµÃ v2 = 5 m/s Ð¡ÇòÓëµØÃæײ»÷ʱËðʧµÄÄÜÁ¿  
?E1 = mv12 - mv22 = ¡Á0.2¡Á£¨240 - 175£©=" 6.5" J       
СÇòÔÚ¿ÕÆøÖÐËðʧµÄ»úеÄÜΪ
?E2 = f£¨2h1 + 2h2£© = 0.5¡Á£¨2¡Á16 + 2¡Á7£© =" " 23 J        
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?E = ?E1 +?E2 = f£¨2h1 + 2h2£©+mv12 -mv22 =" 23" + 6.5 =" 29.5" J   
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¡à mv32 = £¨0.2¡Á10 - 0.5£©¡Á7 =" 10.5"
Ôò ?E = mvo2 ¨Cm v32 = ¡Á0.2¡Á202 - 10.5 =" 40" - 10.5 =" 29.5" J 

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