Cdu 59: M o t v a t r&n dang quay deu quanh true co d i n h A vdri toe goe 30rad/s t h i chiu tae dung ciia mot momen h a m eo Idfn k h o n g doi nen quay c h a m d a n deu va dCfng l a i sau phut i e t momen quan t i n h cua vat r a n doi vdri true A la lOkg.in^ Momen h a m eo \6n bang: A 3,5 N m B 3,0 N m C 2,5 N m D 2,0 N m Giai Goi Y la gia toe goe cua v a t Ta c6: co = a)o+yt = O ^ Y = - ^ = - : ^ = -0,25rad/s- , Theo cong thufc ccr b a n cua chuyen dong quay, t a c6: M = ly = 10.0,25 = 2,5 (N/m) Vay clign dap an C Cdu 60: B i e t dong v i phong xa '(,C c6 chu k i b a n r a 5730 n a m Gia suf mot m i u g6 c6 c6 phong xa 200 p h a n r a / p h u t va m o t m i u g5 k h a c cung loai, cung k h o i liTcfng v d i mau g5 eo do, l a y tCr cay m d i c h a t , eo phong xa 1600 p h a n r a / p h i i t Tuoi cua mKu go c6 da cho l a : A 1910 n a m B 2865 n a m C 11460 n a m D 17190 n a m Giai T a i thdi d i e m cay mdri chat, dp phong xa l a : H o = - ^ = ^No (1) Do phong xa cua mau g5 mdi: u = -— = mX^ At TC(l)va(2)tac6:^ = ANo - ^ (2) " 2T^i2^-L-i-± 1600 ^\ 2' t = = 3.5730-17190 n a m T Vay chgn dap an D Giai Chi tiet de thi TS DH, CD Mon vat If 83'