- Sketch a graph of acceleration against time - a standard cosine graph.
- While the acceleration of the container exceeds downwards, the water will be moving upwards relative to the container.
- Solve the equation for
- Interpret this solution in conjunction with the sketch-graph to find the first two values of for which the acceleration is less than ; i.e. numerically greater than downwards.
- Writing and then , solve the differential equation to find in terms of .
- Use the two values of to find the velocity and the displacement of the container during this phase of the downward acceleration.
- Hence find the displacement of the container relative to the water, giving the minimum height of the wall above the water-level.