Calculate Velocity of Impulse

Hello! I am currently making a 2d game. You move the player with a drag and shoot mechanic. You drag and let go, then the distance between the drag pulse is used in an impulse that moves the player in the opposite direction. So if i drag to the left, the player flies to the right. So now i want to make a path, that predicts, to which point the object will fly (trajectory prediction). I already have a script for it, but its only working if i write down the player velocity manually. But i need the velocity of the player, before it is moving. Can someone help me witht this? Maybe find out the velocity of the impulse? If it is too complicated for this forum, you can also add me on discord, my name is thedvxl#4344.