In my option, research objectives and research questions are essentially the same thing, but hypotheses are more specific. In particular, hypotheses are predictions about how your key concepts are related to each other. So you could have a set of broad research questions, and under each of them you could state testable hypotheses.

Typically research objectives and questions are likely to be used in qualitative and descriptive quantitative studies. Research hypotheses are used in quantitative research studies designed to test a relationship between two or more variables. Researchers match up the objectives, questions and hypotheses use with the type of research they are doing.

Yes, it is quite common—and often advisable—to use objectives, research questions, and hypotheses together in single research. Objectives outline the goals of the study, research questions focus on specific inquiries, and hypotheses propose predictions to test. Integrating these elements can ensure clarity, focus, and hypothesis-driven investigation. That’s said, it is always good to review an intended journal’s style and guidelines before finalizing one’s manuscript. Here is a helpful read.

McGregor, S. L. T. (2018). Understanding and evaluating research: A critical guide. SAGE. https://methods.sagepub.com/book/understanding-and-evaluating-research

Good luck,

Using research questions and objectives together in qualitative research seems appropriate, and research questions and hypotheses go together well in quantitative studies. Qualitative RCT can also have research questions and hypothesis together.

It is a chalenging question and it will be a good feedbacks. In my humble opinion, Each of these issues in turn can be useful in the problem stating and posing a new question at the first step. However, the research objectives are more decisive to create a research study and it will be covered the whole contents appropriately.