Calculating Centripetal Force: 40.0kg Child on 9.0m Ferris Wheel

[jesuslovesu]

A 40.0 kg child on a Ferris wheel rotates four times each minute and the wheel has a radius of 9.0 m.

What force does the seat exert on the child when the child is halfway between the top and bottom?

The answer is 397 N which is 5 N more than the weight of the child, but I have not idea how they got that, anyone have any ideas?

 

[Tide]

HINT: The seat also supplies the centripetal force to keep the child moving in a circular path.