What is a short film?

Our short film has got to be at least 5 minutes long, with a detailed explanation of what the film is about. In actual fact a short film is around 40-45 minutes long. In our 5 minutes we have to make sure we have got everything covered that is asked for, such as the story line of the film, and then the conclusion to the film. Like our film is a documentary on happiness, so meaning by the end of our film we have to make sure we have answered the question "what is happiness?", this will be the conclusion.