PHT bài tập các định luật bảo toàn có lời giải

Câu 1:     !"#$%&  '  ()    *   +  ,-.  /0 #123  4    5 1 6  7 8' /0 #123 & 4   23' 9:4    ;2 , ' Câu 2: ( !26 $:- 8 ,%< 68=#3,;2' >?  @#  2<  A  +  B )' 9:4 g=10m/s 2 ' ()  C+ 8*#.  /DE*C1$ :' /DE*C1F )' Câu 1.(GH  ! /IJ /I K J LA DEM#3M##4N6"#' OP+  Q;2/ /R+ 6 1. mv=   0 # 18+ . vv −= , R+ 2 # 1. mvmvp −== ,, R*+ . mvmvmvppp , , −=−−=−=∆  S,''S,Q';2/ /0 # 1&423 ,  ⇒  ,  R*+ . I K  , T  SS'SQ';2/ Câu 2.(GH ! ,, ,;2 /*C1$:'UJ /*C1F)'UKJ Câu 3:V#A=#W      ,  #4N    6 8X;26 16 @#A=#>G , X  #4N   6  8     ;27M#6@#A=#W   7    Y    B   2Y'  (Z  8   Y@#A=#2 # 1'D *2 1[  @#A =#3333\' LA /DE*C1$:' DC+ 8 UU  ]U   , ,  mv ]   /Q^!'',,',' ,  , J=+ /DE*C1F)' DC+ 8. UKU  ]U   , _ ,  mv ]  , ,',' ,  ]^Q`/ Câu 3.(GH   ,   X;2  , X  , ;2 J_  v J_ , v LA ab\,@#A=#W3>' DEM#M##4N =#+ @#A=#W' LE   , .38+  @#A=#6 1 3  , v v ′ ′ .38+  @#A=#2 # 1' OZ?@#  2Y3YcbQE3A /M#& #+ bA3. Câu 4:     1     !      4    6  8    B  d  , ;26P"#43 :e'f -.  /O1#2P#^ 3:e343&4  G'  fY F    A #Z+ e'  /g*#:eh34 ,' fY F  8   + 1G  4 ?:e'   ,  , p p p p ′ ′ + = + r r r r Qi/. *#Qi/M#.  ,  ,   , ,   , , p p p p m v m v m v m v ′ ′ ′ ′ ⇒ + = + ⇔ + = +  , ,  , ,'X X' ,' X' X X v v v v ′ ′ ′ ′ ⇔ + = + ⇒ = − Q/ O 1333\C+ bA 3. , _ ,, , _  , ,, ,  ,  ,  ,  ,  vmvmvmvm +=+ , _  , _ , , _ , , _  ,, X , jX' ,  ',' ,  'X' ,  X',' ,  vvvv −=⇒+=+ Q,/ LA  b  Q/  3  Q,/  1  b  B  7  .  , k ; l ,k ;v m s v m s ′ ′ ⇒ = = Câu 4.(GH !!' SX    ,;2 2^^' S,  /m  J /J LA /ncFo*C  , ,    ' , , C mv mv A F s− = = − (GF c 3A#Zs3"#42P#+ 13 e' p1&eZ 9A#Z+ e' , X ,  , !' ', ,!' , ,'^' C mv F N s − − ⇒ = = = ' /ps’ = 2cmA+ eF C "qBdG 8+ 1G  4 ?:e3. ( ) ,   , ,  ,  ^ ; , ^ C mv s v F s v m s m s   ′ ′ = − = − = − ≈  ÷   '