Hydrogen is being pumped through a pipe system whose temperature is held at \(273 \mathrm{~K}\). At a section where the pipe diameter is \(10 \mathrm{~mm}\), the absolute pressure and average velocity are \(200 \mathrm{kPa}\) and \(30 \mathrm{~m} / \mathrm{s}\). Find all possible velocities and pressures at a downstream section whose diameter is \(20 \mathrm{~mm}\).