1. The problem statement, all variables and given/known data A spacecraft travelling in free space, at a speed of 6 m s -1 has a mass of 10,100kg (including fuel) A rocket engine on the spacecraft is fired up for 4 seconds, ejecting 100kg of fuel and slowing the spacecraft down to 0.02 m s -1 What is the force in newtons, feing the 4 second burn of the spacecraft. 2. Relevant equations 3. The attempt at a solution I really new to physics, and this is an example question in order to help us understand how to work these type Of equations out. I know that f = m a, however in this case I think the fact that the spacecraft is losing weight needs to be taken into acount. The momentum before is 60,600 kg -1 s -1 As I said before Im really new to physics and being able to understand the reasoning for the formula is my main aim here. Thank you in advance to any help that may be given here.