A fluid flows through a pipe with a varying cross-sectional area. If the velocity of the fluid is \( v_1 = 4 \, \text{m/s} \) at a point where the cross-sectional area is \( A_1 = 2 \, \text{m}^2 \), and the velocity at another point where the cross-sectional area is \( A_2 = 1 \, \text{m}^2 \) is \( v_2 \), what is the velocity \( v_2 \)?