Circular Motion astronaut training

[ThomasMagnus]

During pilot or astronaut training, candidates are rotated around a 10.0m radius and experience a force of eight times their weight (8.0 g’s). At what speed are the trainees rotated?

It was explained to me that the centripetal force (Fc) was equal to the force of gravity (Fg). Why are the centripetal and gravitational forces equal in this question, while not in others?

 

[Delphi51]

Fc = Fg is used to solve orbital motion problems. It does not apply here unless you simply mean to say that Fc = 8*mg (which is correct).
Put in your detailed formula for Fc and solve for the speed.

Another approach is to realize the acceleration must be 8*9.81. Then use centripetal acceleration v²/R = 8*9.81 and solve for v.