This is actually not a homework but it looks like one.So I posted here 1. The problem statement, all variables and given/known data A rocket is pushing a box on empty space. The rocket is exerting a force on the blue colored box.In turn the box is exerting the same force on the rocket.The engine(or fire or whatever) it exerting a force on the rocket.. 2. Relevant equations 3. The attempt at a solution At first the rocket gets close to the box,as it gets closer,the electromagnetic force builds up(the box starts to move) until the force from the engine and electro balance.The rocket moves at a constant velocity even closer to the box the electomagnetic force now exceeds the engine force and move at more acceleration.Again the rocket contacts and do the same.Will it keep bouncing like that if there were no energy loss? And is my explanation right at the first place? What would be a better explanation.I haven't studied such types of collision yet(or any types).So please be descriptive.