Question-

A 79.1 kg astronaut is working on the engines of his ship, which is drifting through space with a constant velocity. The astronaut, wishing to get a better view of the Universe, pushes against the ship and much later finds himself 30.4 m behind the ship. Without a thruster, the only way to return to the ship is to throw his 0.505 kg wrench directly away from the ship. If he throws the wrench with a speed of 20.5 m/s relative to the ship, how long does it take the astronaut to reach the ship?