Answer Happy

Q4. [25 marks] Sphere A of mass mA = 3 kg and sphere B of mass mB = 8.5 kg are attached to light inextensible cords, as shown in Figure Q4. Each cord is attached to a frictionless pivot, and the pivots are arranged so that spheres A and B can collide horizontally when each cord hangs vertically downwards. The distance from each pivot to the centre of mass of spheres A and B are LA= 0.4m and LB = 1.6 m respectively. a) In an attempt to determine quickly the highest position to which sphere B will rise, a fellow student suggests to use the conservation of energy principle considering the potential energy of sphere A at its highest position (1) and the potential energy of sphere B at its highest position (2). Explain why this is not an appropriate way to solve the problem. [3] b) If sphere A is released from rest when 8A = 30°, determine the highest position to which sphere B will rise and the associated largest angle 08. [17] c) If spheres A and B are bonded together after the collision, write a few sentences to explain whether you expect spheres A+B to reach a higher point than sphere B on its own. 0.4 m 30° 23 Figure Q4 (not to scale) 1.6 m [5]