Cdu 59: M o t v a t r i n quay n h a n h dan deu quanh m o t true co dinh, t r o n g 3,14s toe goc cua no tkng tii 120 v6ng/phut den 300 vong/phiit L a y 71 = 3,14 Gia toe g6e cua v a t rSn c6 Idrn l a : D r a d / s l C r a d / s l B 12 r a d / s l A r a d / s l Ta c6: 120 vong/phiit = vong/giay => co, = 47trad/s 300 vong/phut = vong/giay = lOTirad/s Gia toe goc cua v a t r ^ n c6 Idrn \k: CO2 y = — 1071-471 ,/ 2\ = rad/s = t 3,14 Vdy chgn dap an A ^ ^ Cdu 60: Chieu dong t h d i h a i bijfc xa c6 bifdc song 0,452 ^ m va 0,243 ^im vao catot cua mot te bao quang dien K i m loai l a m catot c6 gidi han quang dien 1^ 0,5urn L a y h = 6,625.10-^''J.s, c = S l O W s va m^ = 9,1.10-^^kg V a n toe ban dau CLTC dai cua cac electron quang dien b k n g : D 9,24.10Ws C 2,29.10Ws B l,34.1.0Ws A , l O W s Gidi Ca h a i buTc xa deu gay n e n h i e n tiTgrng quang d i e n , t r o n g X< XQ V i v a n toe ban dau CLTC dai cua cac electron quang dien diTtfc gay bdi biTdrc song ng^n hcfn n e n X = 0,243 ^im Ap dung phifcfng t r i n h A n h x t a n h : he he mv Omax = A + Y |_ mv Omax To suy ra: he he 2.19,875.10 ^Omax -26 9,1.10r 1 ^0,243.10"* 0,5.10" = 9,61.10'(m/s) •Vdy chgn dap an A 52 G i i i Chi tiSt as thi T S D H , CD M6n V S t If