A variable-diameter duct has a flow cross-sectional area of 0.006m² at state 1 and 0.002m² at state 2. Steam at 680 K and 6.0 MPa enters at state 1 at a velocity of 30 m/s, flows steadily through the duct, and leaves at 580 K and 3.0MPa at state 2. 

(a) Determine the velocity (m/s) at state 2, 

(b) Use the NIST software to plot the 6.0 and 3.0 MPa isobars on a T–v plot and indicate the inlet and outlet states using bold dots. Add the dots by hand.