1. The problem statement, all variables and given/known data A passenger at the rear of a train traveling at 15 m/s relative to Earth throws a baseball with a speed of 17 m/s in the direction opposite the motion of the train. What is the velocity of the baseball relative to Earth as it leaves the thrower's hand? Answer in units of m/s. 2. Relevant equations 3. The attempt at a solution Vector of the train is going to the right (15 m/s). Vector of the person throwing the ball is going to the left (17 m/s). Adding the vectors 15 - 17 would give you -2 m/s. I'm having trouble with assigning direction to vectors, so please let me know if I assigned them right in this problem. Thanks!