It was tied in with some kinematics stuff but I couldn't figure it out for the life of me. Info given: Mass of a train (kg) Speed of train (km/h, convert to m/s) Brake is applied with a force (given in N) Brake is applied for time (s) Find the final velocity after braking for t seconds. It was literally the first question on the test. I tried almost everything I could think of. The first (and most logical) thing I tried was taking the force of the brakes and dividing by the mass of the train to get the acceleration, then just plugging that into a kinemeatics equation, Vx=Vox + a*t, but that didn't get me anything close to any of the multiple choice answers. Any ideas?