We could try to separate the interactions to the best of our ability (of course some interactions are always going to be there)
1) To visualize the first one we can say that the carousel is at a standstill and the kid is holding a bar magnet that induces a magnetic field in the middle of the carousel
2) For this one we can let the kid hold a charged ball and the carousel spin around.
3) The last one is where the kid would be allowed to walk through the middle of the carousel holding onto the charged ball