Particles a, b of mass 3m, 2m respectively are attached to the ends of a light inextensible string passing over a smooth pulley. the system is held at rest, the string is taut and the parts of the string not in contact with the pulley are vertical. the system is then released. after b has travelled 5 m it hits and coalesces with a particle of mass 5m at rest. find the impulse in the string. find also the time taken from the impact until the system first comes momentarily to rest. [take g as 10 m/s? ].