Where does g force fit in this centripetal motion question?

[Henrybar]

a car goes around a vertical circle; determine the period of one cycle if the radius= 6m mass=800kg, gravity=9.8m/s^2 gforce = 6g

my attempt at the bottom of circle:
fnet=ma
fn+fg=(mv^2)/r
fn+fg=(4∏^2mr)/t^2
t=√4∏^2mr/fn+fg
t=√4∏^2(800)(6)/(fg+fg) <-----value of fn and fg will be in opposite directions

fn≠fg so either fn or fg has to be greater. If they both = mg at the bottom, do i multiply the gforce here? to which one? I originally thought that the g force would be multiplied to fn since there is acceleration towards the centre, but would that even make sense?

 

[Student100]

a car goes around a vertical circle; determine the period of one cycle if the radius= 6m mass=800kg, gravity=9.8m/s^2 gforce = 6g

my attempt at the bottom of circle:
fnet=ma
fn+fg=(mv^2)/r
fn+fg=(4∏^2mr)/t^2
t=√4∏^2mr/fn+fg
t=√4∏^2(800)(6)/(fg+fg) <-----value of fn and fg will be in opposite directions

fn≠fg so either fn or fg has to be greater. If they both = mg at the bottom, do i multiply the gforce here? to which one? why?

Lets break this problem into parts, first what's the radial acceleration?