how to slow down a spaceship using law of conservation of momentum without a collision?

Fermin Tara: almintaka has the superb answer. so a strategies as macroscopic area, wherein we are residing, is worried, conservation of momentum is inviolate. however, as quickly as you start up off tweeking activities on the limitations of Heisenberg's uncertainty theory, issues are not as tender, and what we evaluate "rules" at the instant are not inevitably real for all time. Any length over those intervals of time and distance isn't attainable with the help of any ability obtainable to us because of the fact any length we would take could exchange the circumstances of what we are observing, and could stress it into the macroscopic international, the place it rather is then compelled to obey the guidelines of our international....Show more

Peggy Sandefer: You would slow down the space ship the same way space ships take off. The law of conservation of momentum states that the sum of momentum in a system does not change over time, expressed mathematically as MiVi=M! fVf Where. M: Mass, V: VelocityInitially, you'll have a single object (space ship) [Mi] moving at a constant velocity [Vi], with the total momentum of the system equal to MiVi. To slow down the space ship, the space ship could launch something in the forward direction. When this happens, the total momentum of the system is equal to Mf1Vf1 + Mf2Vf2, where Mf1 is the new mass of the space ship and Vf1 is the new velocity of the space ship. Mf2 is the mass of the object launched from the space ship and Vf2 is the velocity of the object launched from the space ship. Since we know that, initially, the space ship's momentum is equal to MiVi and that since it's conserved (law of conservation of momentum), MiVi = Mf1Vf1 + Mf2Vf2.We are slowing down the space ship so Vf1 needs to be smaller than Vi. Since this is the case, a greater value for Mf2Vf2 will slow down the ship more because the larger its value, the smaller the value of Mf1Vf1.THEREFORE: To slow down t! he space ship, something needs to be launched from the space s! hip in the exact same direction as the spaceship is currently moving. The faster it is launched or the more mass the projectile has, the more it will slow down the ship. (Keep in mind, the more mass it has, the less mass the space ship will have which actually slows it down less. Increasing the mass of the projectile will slow down the ship more, but not as effectively as increasing the velocity of the object.)As I mentioned before, this is how a rocket takes off. At first it is sitting stationary on the launch pad, then it pushes a great deal of fuel at a high velocity towards the ground, which makes the rocket move in the opposite direction.*Note: V being a velocity means that direction is important, to slow down the ship the object must be launched in the same direction that the ship is moving....Show more

Ronny Dorge: If you are talking about a friction-less atmosphere/environment then you cannot. Otherwise turn the spaceship off? or however you make a spaceship s! top going? but even then it would slow due to friction with the atmosphere.