Think of other models of centripetal acceleration that you have learned. If a ball on a string is swung, its centripetal acceleration is provided by the tension force towards the centre of the orbit. If a satellite is orbiting the earth, its centripetal acceleration is provided by gravitational...
No. That is incorrect. mu*g does not describe any force in this problem, while V^2/R is the definition of centripetal acceleration.
I already provided the answer to the original question.