Giai Do boi giac cua k i n h l a : G = ^ = — = 20 • 0,06 Goc t r o n g t h i e n t h e k h i k h o n g dung k i n h l a : =^ = = 0,25' Vay chon dap an B Cdu 51: M o t v a t r a n quay quanh m o t true co d i n h d i qua v a t co phtfcfng t n n h chuyen dong (p = 10 + t^ (cp t i n h bang r a d , t t i n h b k n g giay) Toe goc va goc m a v a t quay ducfc sau t h d i gian s ke tCf thcfi d i e m t = Ian lirgft l a : A rad/s va 25 r a d B rad/s va 35 r a d C 10 rad/s va 35 r a d D 10 rad/s va 25 r a d Giai So sanh phifdng t r i n h cp = 10 + ( c p t i n h b k n g rad, t t i n h b k n g giay) vdi phifotng t r i n h t o n g quat (p = % + (ii^t + ^yt^ t a difdc cac gia t r i : (Po = lOrad/s; © = 0; = =:> Y = 2rad/s\ M a t khac, phicfng t r i n h toe goc: co = yt • Sau 5s, t a co: co = 2.5 = 10 rad/s A(p = (p-cpo = + t ^ - = 25rad Vdy chgn dap an D Cdu 52: M o t dia p h i n g dang quay quanh true eo d i n h d i qua t a m v ^ vuong goc vcri m a t p h a n g dia v d i toe goe k h o n g d d i M o t d i e m b a t ky n k m d mep dia A k h o n g CO ca gia toe hudtng t a m va gia toe t i e p t u y e n B CO ca gia tdc hudfng t a m va gia toe t i e p t u y e n C c h i c6 gia toe hifdng t a m m a k h o n g co gia tdc t i e p t u y e n D c h i CO gia tdc t i e p tuyen m a k h o n g co gia tdc hirdrng t a m GiSi M o t diem ba't k y n k m d m6p dia chi co gia tdc hifdng t a m m ^ k h o n g CO gia tdc t i e p tuyen Vdy chon dap an C Giii chi tiSt di thi TS DH, CD M6n V$t l( 23