If it’s that straightforward, why haven’t you done it?

1g of acceleration is enormous compared to a child in a merry go round actually.

> And Gemini tested it once as well.

From Wikipedia:

They were able to generate a small amount of artificial gravity, about 0.00015 g

So yes, you need an effect 60 000 times stronger than this.

And you want that to be relatively uniform over the size of an astronaut so you need a very big merry go round.

Nuclear fission is also a basic feature of physics, that doesn't mean engineering a nuclear power plant is straightforward.