Nitrogen gas is flowing in a 50mm diameter pipe at the rate of 0.05kg/s. The nitrogen flows through a partially closed valve installed in the pipe. Just before the nitrogen flows through the valve, the nitrogen is at 15 degress centigrade and 200kPa. The temperature of the nitrogen is essentially unchanged as it flows through the valve but its pressure drops to 170kPa. The pressures of the nitrogen are low enough to treat it as an ideal gas. Determine the velocities of the nitrogen upstream and downstream from the valve.