8 4 A mass hangs vertically from a fixed point by means of a spring, as shown in Fig. 4.1. spring 0000 mass Fig. 4.1 The mass is displaced vertically and then released. The subsequent oscillations of the mass are simple harmonic. The variation with time f of the length / of the spring is shown in Fig. 4.2. 18 17 16 1/cm 15 14 13 + 12+ 0 0.1 0.2 0.3 0.4 0.5 0.6 Fig. 4.2 (a) Use Fig. 4.2 to (i) state two values of t at which the mass is moving downwards with maximum speed, ........... s and f= ......(ii) determine, for these oscillations, the angular frequency @, (iii) show that the maximum speed of the mass is 0.42ms-1. [2] (b) Use data from Fig. 4.2 and (a)(iii) to sketch, on the axes of Fig. 4.3, the variation with displacement x from the equilibrium position of the velocity v of the mass. ms- 0.2 Fig. 4.3 [3] [Total: 8]