Three monitoring wells are used to determine the direction of groundwater flow in a confined aquifer. The piezometric heads in the wells are found to be 52m in well 1, 49m in well 2, and 56m in well 3. Determine the direction of flow.

If two students are running down the hall toward each other, trying to get to class, and they have the same mass and acceleration, what will happen when they collide? will their forces cancel out or will each one experience a reaction?