Ideal incompressible water is flowing in a drainage channel of rectangular cross-section. At one point, the width of the channel is 12 m, the depth of water is 6.0 m, and the speed of the flow is 2.5 m/s. At a point downstream, the width has narrowed to 9.0 m, and the depth of water is 8.0 m. What is the speed of the flow at the second point

Explanation:

The volume of water flowing  per second at two points will be equal as water is incompressible .

A₁ V₁ = A₂ V₂

A₁ and A₂ are cross sectional area at two points and V₁ and V₂ are velocities at the two points

12 x 6 x 2.5 = 9 x 8 x V₂

V₂ = 2.5 m /s .

Hence velocity will remain unchanged .

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