Ok so, all objectives have mass, and all moving objects have momentum. It’s basically a measure of how well an object carries on moving in a certain direction. Like if you roll a ball across the floor, if you give it more force it will have more momentum and will roll further. Unless it hits something, in which case there’s a transfer of momentum. But in any collision or explosion the total momentum will always end up the same, it might just be transferred to whatever has collided!