- #36
zanick
- 383
- 23
so kind of following the analogy .comparison, of pushing bowling balls out the back of a boat (or the rocket)…. and my comment about the fixed power providing a decreasing force and therefor acceleration as velocity goes up. . I know I was not focused on the KE of the bowling balls leaving the ship, but I still have a problem not seeing how what was confirmed to be "constant acceleration " for the constant force, not accelerating the rocket at a constant rate. I know now this can't be, but still can't understand why... can you do a energy inventory for me so I can put this one to bed? thanks!russ_watters said:I think you might be looking at it backwards: the speed of the reaction mass relative to the rocket is the same every time.
But the speed of the reaction mass relative to the starting point (Earth?) is different every time because the rocket's speed is changing. To an observer on Earth, the first reaction projectile moves to the left and the rocket moves to the right. The second reaction projectile moves to the left a little slower. After a while, the reaction projectiles are actually moving to the right even while accelerating the rocket to the right.