1. The problem statement, all variables and given/known data While coasting along a street at .5m/s, Mieko, a 15kg girl in a 5kg trolly, sees a vicious dog in front of her. She has with her only a 3kg bag of sugar which she is bringing home from the store, and throws it with forward velocity of 4m/s relative to her original motion. How fast is she moving after she throws the bag of sugar? whit is her final direction of motion? 2. Relevant equations p = mv 3. The attempt at a solution right so i did p=mv of the trolley (worked out to be 11.5) and then of the bag being thrown (worked out to be 12) the next step confused me. if i divide 11.5 by 12, i get the right answer of .9582 backwards. but i cannot see how that is mathematically correct. now if i use the m1v1i + m2v2i = m1v1f + m2v2f formula, i only get a value half of the correct answer! can someone please explain this to me?