I believe that answer is nitrogen.
Answer:
The angular velocity is 
Explanation:
From the question we are told that
The mass of each astronauts is 
The initial distance between the two astronauts 
Generally the radius is mathematically represented as 
The initial angular velocity is 
The distance between the two astronauts after the rope is pulled is 
Generally the radius is mathematically represented as 
Generally from the law of angular momentum conservation we have that

Here
is the initial moment of inertia of the first astronauts which is equal to
the initial moment of inertia of the second astronauts So

Also
is the initial angular velocity of the first astronauts which is equal to
the initial angular velocity of the second astronauts So

Here
is the final moment of inertia of the first astronauts which is equal to
the final moment of inertia of the second astronauts So

Also
is the final angular velocity of the first astronauts which is equal to
the final angular velocity of the second astronauts So

So

=> 
=> 
=> 
=> 
4 km in 30 min then 8 km in 60min or an hr. so 8km/hr.
Answer: The pressure of the air when compressed is
Explanation:
Boyle's Law: This law states that pressure is inversely proportional to the volume of the gas at constant temperature and number of moles.
(At constant temperature and number of moles)
where,
= initial pressure of gas = 
= final pressure of gas =?
= initial volume of gas = V
= final volume of gas = 
Therefore, the pressure of the air when compressed is