Figure Q6 shows block A of mass 5-kg which is supported by the uniform rod AB which is attached to a spring of constant k = 700 N/m. The system is in static equilibrium in the position shown in Figure Q6. The end A of the rod is depressed (downwards) by 4 mm and released. Assume undamped free vibration. a = 400 mm and b = 225 mm. [Hint: Spring is in tension in the position shown in Figure Q6 before the end A is depressed.] (i) Derive an equation, in standard form, to describe the resulting motion about 0. Calculate the following: (ii) the period of vibration; (iii) the maximum velocity of point A. A a B k