1. The problem statement, all variables and given/known data A 20 metric ton train moves toward the south at 50 m/s. What speed must it travel to have two times its original momentum? 2. Relevant equations Change in momentum = mass(FinalVelocity - InitialVelocity) 3. The attempt at a solution so I thought you would simply times 50 by 2 and get 100 to be the answer, but thats not right. First question is do you have to convert 20 metric tons to kilograms?