#### Question

# A 63.4 kg astronaut is on a space walk...?

A 63.4 kg astronaut is on a space walk when the tether line to the shuttle breaks. The astronaut is able to throw a 10.0 kg oxygen tank in a direction away from the shuttle with a speed of 10.9 m/s, propelling the astronaut back to the shuttle.

Assuming that the astronaut starts from rest, find th final speed of the astronaut after throwing the tank.

Answer in units of m/s

#### Answer

You need to use conservation of momentum.

Momentum (P) = mv.

Work out the momentum of the oxygen tank. The astronaut has the same momentum. You know his mass and his momentum, so his speed = m/P

I won't give you the answer,but will ask you a question.

Why would the astronaut throw an oxygen tank when all he would have to do is open the valve a little and use the tank as a source of propulsion to get back to the shuttle and then use it to slow down when he gets back to the shuttle?