Answer Happy

The 5.0 kg rod BC is attached by pins to two uniform disks as shown. The mass of the large disk is 5.5 kg and that of the smaller disk is 1.0 kg. A spring with spring constant of 45 N/m is attached to the pivot joint at A, which is unstretched at the position shown in Fig. 3(a). 50 mm 50 mm Figure 3(a) (a) By setting the datum at point A, what is the potential energy of the system at the initial position as shown in the figure? Note that you only need to calculate the potential energy of the rod, because the potential energies of the disks do not change in this problem. (3 marks) (b) Knowing that the system is released from rest from the position shown in Fig. 3(a), and the two disks roll without slipping. The large disk rotates through 90° clockwise to the position shown in Fig. 3(b), where point B is directly below point A, and the rod is in a horizontal orientation at this instant. 100 mm B