Undergraduates are not usually expected to produce a research paper that contains original new knowledge like a journal article or dissertation. (There are a few exceptions, but not many.)
In some cases, it simply means, “Go to the library, read up on the topic, and write a coherent essay that supports a plausible conclusion.” However, you might be advised to look at some jounal articles and see what's in them.
I'd also add a caveat. Undergraduates are still learning, and that takes more time. A proficient writer might churn out a good essay in a day or two, but someone who is still learning needs much longer.
How long it will take depends on several factors, so I would not like to give any anwers in numbers of hours.
First, check your school's specifications for the paper.
Second, look for an original topic that lets you do field research.
Third, go interview some people relevant to your topic, and you will probably get some interesting results.
Someone once came to me with a question like this on ethics, and he thought the current range of topics was quite mundane. So he went to the nightclub district and interviewed some bikies. He found their code of honour was a strict ethical code, although it was not very compatible with the government's views. He got an A.