Step 1: Understanding the Concept:
Unit weight (\(\gamma\)) is the weight of a substance per unit volume.
It is the product of the density (\(\rho\)) and the acceleration due to gravity (\(g\)).
Step 2: Key Formula or Approach:
\[ \gamma_w = \rho_w \times g \]
Standard density of water (\(\rho_w\)) = \(1000\text{ kg/m}^3\).
Standard gravity (\(g\)) = \(9.81\text{ m/s}^2\).
Step 3: Detailed Explanation:
\[ \gamma_w = 1000\text{ kg/m}^3 \times 9.81\text{ m/s}^2 = 9810\text{ N/m}^3 \]
To convert to kilo-Newtons (\(kN\)):
\[ \gamma_w = \frac{9810}{1000} = 9.81\text{ kN/m}^3 \]
Step 4: Final Answer:
The approximate unit weight is \(9.81\text{ kN/m}^3\).