Question

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.

Answer 1

The astronaut can throw the hammer in a direction away from the space station. While he is holding the hammer, the total momentum of the astronaut and hammer is 0 kg • m/s. According to the law of conservation of momentum, the total momentum after he throws the hammer must still be 0 kg • m/s. In order for momentum to be conserved, the astronaut will have to move in the opposite direction of the hammer, which will be toward the space station.