 Đề 3 Bài làm Điểm   !"#$%  &"'  ()*+%,-()*+ %."/ 0"%12- 3" %."/3)/4-()*"5-()* %."/3-()*6"%4  "4-7)+8"'  9"4)+83:"$-( *;< $-( -/ 63 = > ? 1 %) @ -A @ "3 = ) @ 1 B C ? < D = - =  @  @ -3 =  @  ? CE9E F  @  =   G @  @ -3 =  ? "-" @ 1 > = $H ? -1I = -A @  ) @  "' 9"4)+83:"$-( *;<$-( -/  ( ) 2 1 4 l k λ = + J"-H--K 9L<-()*< -()*+</9M3'3A> %NC G 9L 2 m T k π = ()* 1 2 k f m π = ()*+ k m ω = /9M3' 2 k F m x kx ma ω = = = GA>% 2 2 2 2 1 1 1 2 2 2 M W m A kA mv ω = = = OG$-"' N+  9L P<Qs 3" Rcm GS*-T""U3V- W 3;-6K J x cm= -E"'  A"-1A-6L "-1A-6L3V-* "-1A-6L"-* ()*+ 2 4 ( / )rad s T π ω π = = 0" 6 ( )A cm= (  ( ) 4 rad π ϕ = − A-6L 6 cos 4 ( ) 4 x t cm π π   = −  ÷   A-6L3V-* 24 sin 4 ( / ) 4 v t cm s π π π   = − −  ÷   A-6L"-* 2 960 cos 4 ( / ) 4 v t cm s π π   = − −  ÷   QX-"' N+ 1A-6L Q) O Y Z O x t cm π π   = +  ÷   K3V -*9"3V-W 3;-6K+-> ,J(> ;-6K+->,J(> 3 t ñ W W= ; V-[-A> t ñ W W W+ = \] 4 ñ W W= ) ]6 10 ( / ) 2 A v cm s ω π = ± = ± R\""' ^ 1 9 cos 2 ( ); 2 x t cm π π   = +  ÷   ( ) π = 2 9sin 2 ( )x t cm "-1A -6L-_71 + ( ) 2 9sin 2 =9 cos 2 ( ) 2 x t t cm π π π   = −  ÷   41 1 2 ϕ ϕ ϕ π ∆ = − = 0" 1 2 0A A A= − = A-6L 0x = `X-)+-6 ]'"-8  a3:":)+ cm K 9[b-83;-6K+1 ( %)+ 2 x ϕ π λ = 'J6  J Y Z O rad π  a X J O π ϕ = c ]6 4,5x cm= dX-)+-6 ]'"3:":)+ OPcm -6I]a"" P<em  3:"$-( *;<$-( -/ K)*U-)+W )b-7-6 I] "' 9"4)+83:"$-( *;<$-( -/  ( ) 0,4 2 1 0,9 (2 1) 4 4 l k k λ = + ⇒ = + c*$U")+ 4k = c*U-)+f 1 5k + = 'J6 . K3V -* 9"3V-W  3; -6 K+ - > ,J(> ; -6 K+ - >,J(> 3 t ñ W W= ; V-[ - A>. P<Qs 3 " Rcm GS* - T""U3V- W  3; -6 K J x cm= - E"'  A" - 1 A -6 L