Help with physics!!!!!!! Well i have this phsyics homework question and i don't understand at all how to solve it, any help/hints would more then appreciated. Thanks in advance. A 2.0-kg bag is held by a string to the ceiling as shown in the diagram below. A 10-g bulled travelling at 200 m/s strikes the stationary bag. The height of the bag after the collision is 10.0 cm. Assuming there is no friction, determine the speed, in mtres per second, of the bag after the collision.