An 85.0 kg astronaut is working on the engines of a
spaceship that is drifting through space with a con-
stant velocity. The astronaut turns away to look at
Earth and several seconds later is 30.0 m behind the
ship, at rest relative to the spaceship. The only way
to return to the ship without a thruster is to throw a
wrench directly away from the ship. If the wrench
has a mass of 0.500 kg, and the astronaut throws the
wrench with a speed of 20.0 m/s, how long does it
take the astronaut lo reach the ship?