An astronaut whose mass is 80 kg carries an empty oxygen tank with a mass of 10 kg. The astronaut throws the tank away with a speed of 2.0 m/s. With what velocity does the astronaut start to move off into space?

22. the top of a cliff is located a distance h above the ground. at a distance h/2 there is a branch that juts out from the side of the cliff, and on this branch a bird's nest is located. two children throw stones at the nest with the same initial speed, one stone straight downward from the top of the cliff and the other stone straight upward from the ground. in the absence of air resistance, which stone hits the nest in the least amount of time?