Calculate the hydrostatic force on a vertical plane submerged in two layers of liquid (oil and water), given their densities and depths.

Step 1: Identify the given parameters and divide the submerged plane into sections.
The vertical plane is submerged in two layers of liquid:

• Top layer: Oil with density $\rho_{\text{oil}} = 800 \text{ kg/m}^3$ and depth $h_{\text{oil}} = 1 \text{ m}$.
• Bottom layer: Water with density $\rho_{\text{water}} = 1000 \text{ kg/m}^3$ and depth $h_{\text{water}} = 2 \text{ m}$. Let the width of the plane be $b$. The acceleration due to gravity is $g = 9.81 \text{ m/s}^2$.

The plane can be