1. The problem statement, all variables and given/known data An astronaut stranded in space throws a 0.70kg tool backwards at -12.0m/s in order to return to her spaceship. If she and her spacesuit together have a total mass of 90kg, how fast and in what direction is she moving after throwing the tool? So Et=Et I'm not sure what to use. It has to be one that uses mass and velocity, im just not sure.