The concept of "work" and types of energy I have read the other posts regarding the concept of work and still don't understand why distance has anything to do with it. Anyway, I thought that maybe an explanation of the following might help: Suppose you have a 1kg space-ship in an empty universe, with zero velocity in some frame of reference. Then it consumes its rocket, which is able to push with 1 Newton force for 1 second**. The ship is now going 1meter / second and has a total energy of 1/2*mv^2 = 0.5 Joules kinetic energy. Now suppose the same scenario, but the ship initially has a 1 meter / second velocity. The final velocity is 2 meters / second = 1/2*mv^2 = 2 Joules. So in the first case, the transition of chemical energy to kinetic energy results in a gain of 0.5 Joules for the ship, whereas in the second case, a gain of 1.5 Joules occurs. **Is it safe to say that a rocket can provide the same impulse, regardless of starting velocity?