What is the difference between "Hang on" and "Just a moment"?
Both "hang on" and "just a moment" can be used to tell someone to wait. However in this case, the expression "hang on" indicates a sudden realization or understanding of something. So here, he suddenly realizes that he has a scooter he can ride, instead of having to walk. Ex: Hang on, I just remembered that I don't have school today. The phrase "just a moment" is usually just used to tell someone to wait, and not to express a sudden understanding of something. It can also indicate a short period of time. Ex: Just a moment, I need to put my shoes on before we leave. Ex: The doctor will be ready for you in just a moment.