An astronaut on a space walk floats a little too far away from the space station. Without air to push against, he cannot paddle back. However, the astronaut is holding a hammer. Explain how the astronaut could use the hammer to move and why this will get him back to the space station

Astronaut can utilize the Newton's third law of motion to his rescue. He can move his hammer in the backward direction( of which he intends to go) and thus move forward.

Explanation

Caught in such a critical situation, Astronaut's hammer can come to his rescue. He/she can utilize the Newtonian's third law to his advantage.

Newton's third law of the motion says that every action has an equal and opposite reaction provide the action and reaction does not act on the same body. Modern-day rockets and spacecraft work on the practical application of the above-mentioned principle.

Thus utilizing the above-mentioned principle, he could repeatedly tend to throw (but not actually throwing else he would lose his hammer too) in the backward direction to generate an equal and opposite forward momentum. Since space has no medium, resistance would supposedly be zero. Hence even small force generated can make him drift towards his spaceship.