A mass A is released from the top of a frictionless inclined plane 18 m long and reaches the bottom 3 sec later. At the instant when A is released, a second mass B is projected upwards along the plane from the bottom with a certain initial velocity. The mass B travels a distance up the plane, stops and returns to the bottom so that it arrives simultaneously with A. The two masses do not collide. Find the acc. and initial velocity of B. (How far up the inclined plane does B travel?)