#### Submerged Gates: Interactive Simulations

These simulations were prepared using Mathematica. Download the free Wolfram player, and then download the simulation CDF file (link given below or click on figure to download). Try to predict the behavior when a parameter changes before using a slider to change that parameter. Screencasts below explain how to use these simulations.

##### Simulation: Forces on a Partially-Submerged Gate

Using forces balances on submerged surfaces, determine how changing fluid height, the weight of the gate, and the angle of the gate affect the applied force needed to keep the gate closed.

Try to answer these questions before determining the answer with the simulation. We suggest that you write down the reasons for your answers.

1. If the angle of the gate increases, will the force of the gate increase, decrease, or stay the same?
2. If the gate weight decreases, will the tension in the cable increase, decrease, or stay the same?
3. If the water height decreases, will the tension in the cable increase, decrease, or stay the same?
##### Simulation: Forces on a Completely-Submerged Gate

A gate hinged at the top is submerged under water. The gate is 2.5 meters long and 1 meter wide. This Demonstration calculates the force that must be applied to keep the gate closed. Use the sliders to set the water height and the gate weight. Check the “show distances” box to display distances.

Try to answer these questions before determining the answer with the simulation. We suggest that you write down the reasons for your answers.

1. If the gate weight decreases, will the applied force that keeps the gate closed increase, decrease, or stay the same?
2. If the water height decreases, will the applied force that keeps the gate closed increase, decrease, or stay the same?