According to Bernoulli's theorem , the pressure of drop is given as

∆P = (ρ/2) [v1² - v2²]

also , A1v1 = A2v2

where A , v and ρ shows cross section area , velocity and density of liquid.

A2 = π(0.1)² , A1 = π(0.04)²

now, A1v1 = A2v2

(0.04)² v1 = (0.1)²v2

25v2= 4v1 ------(1)

now, ∆P = (ρ/2)[v1² - 4/25 v1²]

= (ρ/2) [21/25]v1²

now, here pressure drop across it's end is 10N/m² , e.g., ∆P = 10N/m² and ρ = 1.25 × 10³ Kg/m³

so, 10 = (1.25 × 10³/2 ) × (21/25) v1²

10 = 625 × 21/25 v1²

v1² = 10/25 × 21

v1 = √{2/105} m/s