A mass m is hanging on a string that passes over a pulley and is then attached to another mass 3m that is resting on a horizontal table (along with the pulley). Neglect friction. Mass m is held montionless and is then released. When it has fallen a distance h, it will have a speed v which can be calculated from the formula

Question

(a) v=sqrt((gh)/4)
(b) v=sqrt((gh)/2)
(c) v=sqrt(gh)
(d) v=sqrt(2gh)
(e) None of these are correct.