A moving body of mass m and velocity 3 km/h collides with a rest body of mass 2m and sticks to it. Now the combined mass starts to move. What will be the combined velocity
Converting the given velocities to SI units, the initial velocity of the moving body is (3 km/h) = (3/3.6) m/s = 5/6 m/s. Using conservation of momentum, (m*(5/6) + 2m0) = 3mv', where v' is the final velocity of the combined mass. Solving this, we get v' = (5/18) m/s = 1 km/h.