15. a) The two blocks of mass 20 kg and 40 kg are connected by a rope passing over a friction less pulley as shown in Fig. 15(a). Assuming co-efficient of friction as 0.3 for all contact surfaces. Find the tension in the string, acceleration of the system. Also compute the velocity of the system after 4 second starting from the rest. (OR) 20kg, 10.25 30 Fig. 15(a) 60+ 40k (16)