A plank of length 2L and mass 2m is hinged at its lower end, lies on a frictionless table. A ball of mass m and velocity to strikes its end as shown and its turns back along the same line with velocity f. Moment of inertia of plank of length 1 and mass m, 1 = 1/2ml. 13) Find the final velocity of the ball v, assuming that mechanical energy is conserved. B) - 9/0 3 C) 210 5 A) 210 3 14) Find the angular velocity of the plank after the colision. - D) - m E) - 300 2m 2L