If you were, say a person moving forward in space and threw something, would you still go backwards? I know that fuel would push you forward (like a rocket's propulsion system) and a fire extinguisher would also propel you in the opposite direction, but do you need a source of fuel for that to happen? In other words, if you had a bag of stuff and you (just your body, not in a vehicle of any sort) are already in motion in space, (going forward) could you slow yourself down by throwing the things in that bag in the opposite direction that you are moving? Thanks!!