試題詳解

2. Block A (0.40 kg) and block B (0.30 kg) are on a frictionless table (see figure). Spring 1 connects block A to a frictionless peg at O and spring 2 connects block A and block B. When the blocks are in uniform circular motion about O, the springs have lengths of 0.60 m and 0.40 m, as shown. The springs are ideal and massless, and the linear speed of block B is 2.0 m/s. If the spring constant of spring 1 is equal to 30 N/m, the unstretched length of spring 1 is closest to
(A) 0.51 m,
(B)0.53 m,
(C) 0.55 m,
(D) 0.54 m,
(E) 0.52 m. 00000000003 0.60 m heQ00- -0.40 m-